{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80603","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.772Z","datePublished":"2026-08-28T06:48:29.158Z","dateUpdated":"2026-08-29T06:21:14.540Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:21:14.540Z"},"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"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"},"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_irc.c"],"versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"437e0a3854b3a44ec15afa9ab88ec215adf3a2fd","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"2b70f61f569bb29acb380e6f616a1bbdee15668f","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"2393f0bd7a467ad475598f3a5b9de27ca36e3037","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"aff589556ed772cb1c0c2d7b4d91ec45c0c39416","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"eeef3b81f449560653662df2dde6f6fe247c5365","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a","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_conntrack_irc.c"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"5.10.261","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.212","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.178","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.145","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.97","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.40","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"2.6.12","versionEndExcluding":"5.10.261"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2"}]}]}],"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"}}}}