CVE-2026-98485

Published: October 21, 2026Last modified: October 21, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_rt: fix zero-address non-strict match out-of-bounds read rt_mt6_check() permits rules to be configured with rtinfo->addrnr == 0 even when address matching (IP6T_RT_FST_MASK) is requested. In the IP6T_RT_FST_NSTRICT path, rt_mt6() evaluates packet routing addresses against rtinfo->addrs[i] and terminates backwards at the bottom of the loop: if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) { i++; } if (i == rtinfo->addrnr) break; When addrnr is 0, if the first packet address matches rtinfo->addrs[0], i is incremented to 1. Because i is now strictly greater than addrnr (0), the loop termination condition (i == rtinfo->addrnr) is bypassed and will never be satisfied. If a crafted IPv6 packet contains matching routing addresses, i will advance past IP6T_RT_HOPS (16). The subsequent call to ipv6_addr_equal() reads beyond struct ip6t_rt, triggering UBSAN/KASAN out-of-bounds warnings or kernel panics. Fix this by: 1. Rejecting rules in rt_mt6_check() where IP6T_RT_FST_MASK is set but rtinfo->addrnr is zero. 2. In rt_mt6(), moving the termination condition (i < rtinfo->addrnr) into the for-loop header condition and removing the backwards break at the end of the loop body.

Severity score breakdown

ParameterValue
Base score7.1
Attack VectorLOCAL
Attack complexityLOW
Privileges requiredLOW
User interactionNONE
ScopeUNCHANGED
ConfidentialityHIGH
Integrity impactNONE
Availability impactHIGH
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Status

ProductReleasePackageStatus
Alpaquita Linux23 LTSlinux-ltsFixed (6.1.189-r0)
25 LTSlinux-ltsFixed (6.12.112-r0)
Streamlinux-ltsFixed (6.18.55-r0)

References

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