{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23139", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.972Z", "datePublished": "2026-02-14T15:22:24.059Z", "dateUpdated": "2026-08-05T12:20:21.709Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:21.709Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conncount: update last_gc only when GC has been performed\n\nCurrently last_gc is being updated everytime a new connection is\ntracked, that means that it is updated even if a GC wasn't performed.\nWith a sufficiently high packet rate, it is possible to always bypass\nthe GC, causing the list to grow infinitely.\n\nUpdate the last_gc value only when a GC has been actually performed." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerability is triggered by network packets hitting connlimit rules (xt_connlimit, nft_connlimit) or OVS zone limits. A remote unauthenticated attacker can send a flood of packets to trigger the unbounded list growth.\nAC:L - The attacker fully controls the packet rate needed to bypass GC. The nf_conncount module is only loaded when connlimit is in use, so its deployment inherently implies connlimit rules exist. Exploitation is completely reliable.\nPR:N - No authentication or privileges are needed to send network packets that match connlimit rules. The attack is in the packet processing path, not the rule configuration path.\nUI:N - No user interaction is required. The attacker autonomously sends packets to trigger the vulnerability.\nS:U - The impact (kernel memory exhaustion) stays within the kernel's security boundary. No cross-boundary impact such as VM escape.\nC:N - This is a resource exhaustion bug where stale connections are never garbage collected. No information is disclosed to the attacker.\nI:N - No data modification or memory corruption occurs. The list simply grows unboundedly but the entries themselves are well-formed.\nA:H - The connection list grows infinitely, exhausting kernel slab memory via unbounded GFP_ATOMIC allocations. This leads to OOM conditions, system instability, and potential kernel panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_conncount.c" ], "versions": [ { "version": "f106694733c66a48740c25bc4e212e9b2ea364ce", "lessThan": "2c7c71113ed6d3e2f3aca4c088f22283016ff34f", "status": "affected", "versionType": "git" }, { "version": "be69850b461e7b491d87a22e33ab76fdd04b725e", "lessThan": "c4cde57c8affdcca5bcff53a1047e15d268bdca1", "status": "affected", "versionType": "git" }, { "version": "d265929930e2ffafc744c0ae05fb70acd53be1ee", "lessThan": "9f45588993d7f115280fc726119ca86fba32a811", "status": "affected", "versionType": "git" }, { "version": "d265929930e2ffafc744c0ae05fb70acd53be1ee", "lessThan": "3cd717359e56f82f06cbf8279b47a7d79880c6f3", "status": "affected", "versionType": "git" }, { "version": "d265929930e2ffafc744c0ae05fb70acd53be1ee", "lessThan": "26a82dce2beee39c43c109d9647e16f49cb02a35", "status": "affected", "versionType": "git" }, { "version": "d265929930e2ffafc744c0ae05fb70acd53be1ee", "lessThan": "8bdafdf4900040a81422056cabe5e00a37bd101a", "status": "affected", "versionType": "git" }, { "version": "d265929930e2ffafc744c0ae05fb70acd53be1ee", "lessThan": "7811ba452402d58628e68faedf38745b3d485e3c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_conncount.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.161", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.121", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.66", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.6", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.1.161" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.121" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.66" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.18.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/2c7c71113ed6d3e2f3aca4c088f22283016ff34f" }, { "url": "https://git.kernel.org/stable/c/c4cde57c8affdcca5bcff53a1047e15d268bdca1" }, { "url": "https://git.kernel.org/stable/c/9f45588993d7f115280fc726119ca86fba32a811" }, { "url": "https://git.kernel.org/stable/c/3cd717359e56f82f06cbf8279b47a7d79880c6f3" }, { "url": "https://git.kernel.org/stable/c/26a82dce2beee39c43c109d9647e16f49cb02a35" }, { "url": "https://git.kernel.org/stable/c/8bdafdf4900040a81422056cabe5e00a37bd101a" }, { "url": "https://git.kernel.org/stable/c/7811ba452402d58628e68faedf38745b3d485e3c" } ], "title": "netfilter: nf_conncount: update last_gc only when GC has been performed", "x_generator": { "engine": "bippy-1.2.0" } } } }