CVE-2026-80603
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel, the parse_dcc() function in netfilter nf_conntrack_irc had an off-by-one error leading to an out-of-bounds read. It treated the end pointer as inclusive, while the caller passed a pointer one past the last valid byte. The fix changes the loop to strict less-than, consistent with the caller's convention.
Risk Assessment
This could lead to reading uninitialized memory, potentially causing incorrect IRC connection tracking and, in the future, a real out-of-bounds read.
Recommendation
Install the updated Linux kernel with the fix to eliminate the out-of-bounds read risk in the nf_conntrack_irc module.
Original NVD description (English source)
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.