Out-of-bounds Read Affecting kernel-livepatch-6.1.189-236.399 package, versions <1:1.0-0.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.17% (7th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELLIVEPATCH61189236399-21815067
  • published29 Oct 2026
  • disclosed18 Oct 2026

Introduced: 18 Oct 2026

NewCVE-2026-98485  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-livepatch-6.1.189-236.399 to version 1:1.0-0.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3336.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-livepatch-6.1.189-236.399 package and not the kernel-livepatch-6.1.189-236.399 package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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, &amp;rtinfo-&gt;addrs[i])) {
    i++;
}
if (i == rtinfo-&gt;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.

CVSS Base Scores

version 3.1