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CVE-2026-80603

netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read parse_dcc() treats data_end as an inclusive end pointer, but its only caller passes data_limit = ib_ptr + datalen, which points one past the last valid byte. The newline search loop iterates while tmp <= data_end, so when no newline is present, *tmp is read at tmp == data_end, one byte beyond the region filled by skb_header_pointer(). irc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is capped at MAX_SEARCH_SIZE, so the stray read does not fault. The byte is uninitialized or stale; if it contains an ASCII digit, simple_strtoul will consume it and produce a wrong DCC IP or port in the conntrack expectation. The extra allocation byte is also a fragile guard: if the cap or allocation size changes, this becomes a real out-of-bounds read. Change the loop and its post-loop check to use strict less-than, consistent with the caller's exclusive-end convention. Update the function comment accordingly.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 437e0a3854b3a44ec15afa9ab88ec215adf3a2fd; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 2b70f61f569bb29acb380e6f616a1bbdee15668f; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 2393f0bd7a467ad475598f3a5b9de27ca36e3037; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in aff589556ed772cb1c0c2d7b4d91ec45c0c39416; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in eeef3b81f449560653662df2dde6f6fe247c5365; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a

  • Linux Linux

    2.6.12

  • KernelLinux

    From 2.6.12 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5

References 8

git.kernel.org