224 lines
13 KiB
JSON
224 lines
13 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-93105",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-09-17T16:02:15.085Z",
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"datePublished": "2026-09-17T16:11:16.442Z",
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"dateUpdated": "2026-10-30T12:36:00.346Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-10-30T12:36:00.346Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nesp: do not unref managed frag pages in esp_ssg_unref()\n\nesp_ssg_unref() releases the page references held on the source\nscatterlist after the AEAD operation completes. It calls\nskb_page_unref() on every frag page for an out-of-place transform\n(req->src != req->dst), and in the error path of esp_output_tail()\n(already_unref == true) on the request's own scatterlist.\n\nThis is wrong when the skb carries managed frags\n(SKBFL_MANAGED_FRAG_REFS). Managed frags are owned by a zerocopy ubuf\nand the skb does not hold a per-frag page reference; io_uring SEND_ZC\nwith a registered buffer attaches the bvec pages this way via\nio_sg_from_iter(). The rest of the stack honours this invariant:\nskb_release_data() skips the per-frag unref when SKBFL_MANAGED_FRAG_REFS\nis set, and skb_zcopy_managed() is the guard used at the other unref\nsites.\n\nesp_ssg_unref() is missing that guard, so for a managed-frag skb it\ndrops a page reference the skb never acquired. This can underflow the\npage reference count and free a page that is still in use.\n\nGuard the function with skb_zcopy_managed() so both unref paths are\nskipped for managed-frag skbs, matching skb_release_data()."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The extra unref is reached from IORING_OP_SEND_ZC/SENDMSG_ZC with IORING_RECVSEND_FIXED_BUF: io_sendmsg_zc() -> sock_sendmsg() -> tcp_sendmsg_locked() -> xfrm_output() -> esp_output_tail() -> esp_ssg_unref(). io_sg_from_iter() is the only site that sets SKBFL_MANAGED_FRAG_REFS; esp_input() never calls esp_ssg_unref(), so a remote ESP packet cannot supply the buggy skb.\nAC:L - tcp_stream_alloc_skb() allocates MAX_TCP_HEADER then skb_reserve()s all of it, so a SEND_ZC TCP skb has ~0 tailroom. esp_output_head() therefore takes inplace=false (tailen > tailroom, nr_frags < MAX_SKB_FRAGS, data_len+tailen <= PAGE_SIZE), after which esp_output_tail() replaces the frags and esp_ssg_unref() always drops the managed pages. The attacker chooses the send size.\nPR:L - io_uring_setup() allows IORING_OP_SEND_ZC when sysctl_io_uring_disabled==0 (default); no capability is checked on that send path. An ESP SA is also required: the attacker can add one in a user+net namespace because xfrm_user_rcv_msg() only tests netlink_net_capable(CAP_NET_ADMIN) against the netns user_ns, or can send through an already-installed IPsec policy.\nUI:N - The attacker registers the buffer with IORING_REGISTER_BUFFERS, submits SEND_ZC, and if needed installs the XFRM state/policy; no other user must open a file, mount a volume, or otherwise act.\nS:U - esp_ssg_unref()'s extra put_page() corrupts host kernel page refcounts. That is a conventional local privilege escalation inside the same kernel, not a KVM/Xen guest-to-host or IOMMU-scope change.\nC:H - After the out-of-place transform, esp_ssg_unref() calls skb_page_unref() on every source sg page past skb->data. Those pages were attached by io_sg_from_iter() without a per-frag get_page(), so the extra put underflows the refcount of still-mapped IORING_REGISTER_BUFFERS pages and frees memory the attacker can read.\nI:H - The same extra skb_page_unref() frees registered-buffer pages that remain in the io_uring bvec and the attacker's userspace mapping, so the page can be reallocated and overwritten, giving an arbitrary write and control-flow hijack.\nA:H - The extra put_page() on managed frag pages underflows the page refcount and frees a page still in use, which oopses with bad page state even when the use-after-free is not turned into a full memory-corruption exploit."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/ipv4/esp4.c",
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"net/ipv6/esp6.c"
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],
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"versions": [
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "cb375965800d474c0281a2e92c43c724fce9f463",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "201bdf10ae92e7cbd524adf8c0323e2a963d5fd7",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "3ec55f0c8a6a543cf660584d1346e11f6311ee59",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "1ad6456898f6e6cf58be83bdb607acb1119a9cd1",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
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"lessThan": "21697720ff43b8dfa25b8e8d9ca7f56f4597fc80",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"net/ipv4/esp4.c",
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"net/ipv6/esp6.c"
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],
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"versions": [
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{
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"version": "4.11",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "4.11",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.1.191",
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"lessThanOrEqual": "6.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.160",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.114",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.57",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2.6",
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"lessThanOrEqual": "7.2.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.3",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.11",
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"versionEndExcluding": "6.1.191"
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/cb375965800d474c0281a2e92c43c724fce9f463"
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},
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{
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"url": "https://git.kernel.org/stable/c/201bdf10ae92e7cbd524adf8c0323e2a963d5fd7"
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},
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{
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"url": "https://git.kernel.org/stable/c/3ec55f0c8a6a543cf660584d1346e11f6311ee59"
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},
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{
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"url": "https://git.kernel.org/stable/c/1ad6456898f6e6cf58be83bdb607acb1119a9cd1"
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},
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{
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"url": "https://git.kernel.org/stable/c/26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf"
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},
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{
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"url": "https://git.kernel.org/stable/c/21697720ff43b8dfa25b8e8d9ca7f56f4597fc80"
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}
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],
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"title": "esp: do not unref managed frag pages in esp_ssg_unref()",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |