{"api_version":"1","generated_at":"2026-08-29T12:12:57+00:00","cve":"CVE-2026-80603","urls":{"html":"https://cve.report/CVE-2026-80603","api":"https://cve.report/api/cve/CVE-2026-80603.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80603","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80603"},"summary":{"title":"netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read\n\nparse_dcc() treats data_end as an inclusive end pointer, but its only\ncaller passes data_limit = ib_ptr + datalen, which points one past the\nlast valid byte.\n\nThe newline search loop iterates while tmp <= data_end, so when no\nnewline is present, *tmp is read at tmp == data_end, one byte beyond\nthe region filled by skb_header_pointer().\n\nirc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is\ncapped at MAX_SEARCH_SIZE, so the stray read does not fault.  The byte\nis uninitialized or stale; if it contains an ASCII digit, simple_strtoul\nwill consume it and produce a wrong DCC IP or port in the conntrack\nexpectation.  The extra allocation byte is also a fragile guard: if the\ncap or allocation size changes, this becomes a real out-of-bounds read.\n\nChange the loop and its post-loop check to use strict less-than,\nconsistent with the caller's exclusive-end convention.  Update the\nfunction comment accordingly.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-28 08:16:44","updated_at":"2026-08-29 07:16:45"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","data":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fd","name":"https://git.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037","name":"https://git.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668f","name":"https://git.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e","name":"https://git.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365","name":"https://git.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a","name":"https://git.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1","name":"https://git.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416","name":"https://git.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80603","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80603","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 437e0a3854b3a44ec15afa9ab88ec215adf3a2fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 2b70f61f569bb29acb380e6f616a1bbdee15668f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80603","cve":"CVE-2026-80603","epss":"0.001760000","percentile":"0.072380000","score_date":"2026-08-28","updated_at":"2026-08-29 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the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read\n\nparse_dcc() treats data_end as an inclusive end pointer, but its only\ncaller passes data_limit = ib_ptr + datalen, which points one past the\nlast valid byte.\n\nThe newline search loop iterates while tmp <= data_end, so when no\nnewline is present, *tmp is read at tmp == data_end, one byte beyond\nthe region filled by skb_header_pointer().\n\nirc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is\ncapped at MAX_SEARCH_SIZE, so the stray read does not fault.  The byte\nis uninitialized or stale; if it contains an ASCII digit, simple_strtoul\nwill consume it and produce a wrong DCC IP or port in the conntrack\nexpectation.  The extra allocation byte is also a fragile guard: if the\ncap or allocation size changes, this becomes a real out-of-bounds read.\n\nChange the loop and its post-loop check to use strict less-than,\nconsistent with the caller's exclusive-end convention.  Update the\nfunction comment accordingly."}],"metrics":[{"cvssV3_1":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The bug is reached from attacker-controlled TCP payloads on IPv4 flows processed by nf_confirm() (POST_ROUTING/LOCAL_IN) when the IRC conntrack helper is attached, e.g. on an IRC-exposed host or NAT/firewall handling IRC/DCC through netfilter.\nAC:L - Once the IRC helper is active on a tracked flow, exploitation is deterministic: the attacker completes a TCP handshake, sends a crafted client-to-server PRIVMSG/CTCP DCC without a newline at the copy boundary, and can plant the stale byte via the shared global irc_buffer.\nPR:N - No local account or kernel capabilities are required; a remote peer only needs to send network traffic on a connection where the administrator has enabled the IRC helper. Helper configuration is deployment state, not attacker privilege.\nUI:N - No victim-side clicks, mounts, or other interactive actions are needed beyond normal network reachability; the attacker supplies the malicious IRC/DCC payload directly over the established TCP session.\nS:U - Impact is confined to the kernel/netfilter security domain of the affected host (conntrack parsing and expectations). It does not cross VM, IOMMU, or other separate security-authority boundaries.\nC:H - parse_dcc() performs a one-byte out-of-bounds read past skb_header_pointer()'s copied region into stale kmalloc data in the shared irc_buffer, exposing uninitialized or prior-session bytes that can influence subsequent parsing.\nI:H - If the overread byte is an ASCII digit, simple_strtoul() misparses the DCC address/port and can install incorrect nf_conntrack expectations, altering NAT/firewall pinholes rather than only reading memory.\nA:N - The overread is bounded by the deliberately oversized kmalloc guard (MAX_SEARCH_SIZE+1) and the fix commit states the stray access does not fault; this issue does not directly cause kernel oops, panic, or hang."}]}],"providerMetadata":{"dateUpdated":"2026-08-29T06:21:14.540Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e"},{"url":"https://git.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fd"},{"url":"https://git.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1"},{"url":"https://git.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668f"},{"url":"https://git.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037"},{"url":"https://git.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416"},{"url":"https://git.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365"},{"url":"https://git.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a"}],"title":"netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80603","datePublished":"2026-08-28T06:48:29.158Z","dateReserved":"2026-08-26T14:34:25.772Z","dateUpdated":"2026-08-29T06:21:14.540Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-28 08:16:44","lastModifiedDate":"2026-08-29 07:16:45","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80603","Ordinal":"1","Title":"netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read","CVE":"CVE-2026-80603","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80603","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read\n\nparse_dcc() treats data_end as an inclusive end pointer, but its only\ncaller passes data_limit = ib_ptr + datalen, which points one past the\nlast valid byte.\n\nThe newline search loop iterates while tmp <= data_end, so when no\nnewline is present, *tmp is read at tmp == data_end, one byte beyond\nthe region filled by skb_header_pointer().\n\nirc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is\ncapped at MAX_SEARCH_SIZE, so the stray read does not fault.  The byte\nis uninitialized or stale; if it contains an ASCII digit, simple_strtoul\nwill consume it and produce a wrong DCC IP or port in the conntrack\nexpectation.  The extra allocation byte is also a fragile guard: if the\ncap or allocation size changes, this becomes a real out-of-bounds read.\n\nChange the loop and its post-loop check to use strict less-than,\nconsistent with the caller's exclusive-end convention.  Update the\nfunction comment accordingly.","Type":"Description","Title":"netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read"}]}}}