CVE-2026-64538: linux

CVSS: UnknownReceived
AliasesUBUNTU-CVE-2026-64538DEBIAN-CVE-2026-64538
Published 27-07-2026Last modified 15-10-2026
Open JSON

Vulnerability summary

CVE-2026-64538 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.3% of scored vulnerabilities.

Overall risk
0/100
0100
Minimal · default modelHow is this calculated?
CVSS score
Not scored
010
No CVSS score recorded
EPSS score
0.20%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 28 · Related 26
MGASA-2026-0336MGASA-2026-0337OPENSUSE-SU-2026:11476-1OPENSUSE-SU-2026:21910-1SUSE-SU-2026:23477-1SUSE-SU-2026:23481-1

Timeline

  1. 27-07-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix null-ptr-deref in fib6_nh_mtu_change(). fib6_nh_mtu_change() re-fetches idev via __in6_dev_get(arg->dev) and dereferences idev->cnf.mtu6 without a NULL check. addrconf_ifdown() clears dev->ip6_ptr with RCU_INIT_POINTER() after rt6_disable_ip() has released tb6_lock, so the RA-driven MTU walk can observe a NULL idev and oops. The caller rt6_mtu_change_route() guards its own __in6_dev_get(), but this re-fetch is unguarded; nexthop-backed routes survive addrconf_ifdown()'s flush, so the walk still reaches it after ip6_ptr is nulled. Return 0 when idev is NULL, matching rt6_mtu_change_route() and the fib6_mtu() fix in commit 5ad509c1fdad ("ipv6: Fix null-ptr-deref in fib6_mtu()."). Oops: general protection fault, ... KASAN: null-ptr-deref in range [0x00000000000002a8-0x00000000000002af] RIP: 0010:fib6_nh_mtu_change+0x203/0x990 rt6_mtu_change_route+0x141/0x1d0 __fib6_clean_all+0xd0/0x160 rt6_mtu_change+0xb4/0x100 ndisc_router_discovery+0x24b5/0x2cb0 icmpv6_rcv+0x12e9/0x1710 ipv6_rcv+0x39b/0x410

CVSS metrics

Risk metrics not yet published.

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

+0.01 pp

From 0.19% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.20%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu165 products
  • linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-38.38
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1014.14
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linux< 6.1.180-1 | < 6.12.100-1 | < 7.1.5-1
  • linux-6.12< 6.12.100-1~deb12u1
Linux1 product
  • linux≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < d08d019f2f43a6f9a71e81868bbc326b3afaf37b | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < 1451deca9896957159f0666520a792c1b861af4f | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < b2c70dd3326809429b709a9c7e9220d29923051a | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < 302d57ed7872838b40e56a868fb4c7da7da606e9 | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < 80600b5d0f3ecb9324120dc95b5e915130f516c5 | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < b0d0eb13a0441a8ebf4f227843deaf494f1e2c33 | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < 6428634f7a0b7878144b4925c37856bef3224967 | ≥ c0b220cf7d80eb8a36ae9f12cae6df4577a6814e, < 46c3b8191aad3d032776bf3bebf03efdf5f4b905 | 5.3

3 vendors · 168 products

References

29 links
Show all 29 references