CVE-2026-74561

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-15. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush

nh_rt_cache_flush() walks nh->f6i_list during an RTNL-serialized nexthop replace without holding nh->lock, racing the unlocked IPv6 route add/delete that mutate the list under nh->lock and free fib6_info entries (nh_rt_cache_flush() is inlined into rtm_new_nexthop()):

BUG: KASAN: slab-use-after-free in nh_rt_cache_flush (net/ipv4/nexthop.c:2243) Read of size 8 at addr ffff888012953e18 by task exploit/146 nh_rt_cache_flush (net/ipv4/nexthop.c:2243) replace_nexthop (net/ipv4/nexthop.c:2610) rtm_new_nexthop (net/ipv4/nexthop.c:3323) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)

Unlike the other f6i_list walks, this one bumps each route's sernum via fib6_update_sernum_upto_root(), which needs tb6_lock; taking nh->lock around it would invert the established tb6_lock -> nh->lock order and deadlock. As the only purpose is to invalidate cached dsts, bump the IPv6 sernum for the whole netns with rt_genid_bump_ipv6() instead, mirroring the rt_cache_flush() already done for IPv4 just above.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

Advisory Details (2)

Auto-updated Aug 17, 2026
No patch confirmed yet.
generic

nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4787a6d2629b4e8c0b6bacab1f75c1660eca44d9
generic

nexthop: avoid unlocked f6i_list walk in nh_rt_cache_flush - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/44f53e4331a30fabc38a411fae7524341b618db3

Vendor Advisories for CVE-2026-74561(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 29× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 23:21 UTCEG score recompute
  2. 2026-08-20 23:21 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 10:39 UTCGHSA enrichment
  5. 2026-08-19 21:57 UTCEG score recompute
  6. 2026-08-19 21:57 UTCGHSA enrichment
  7. 2026-08-19 17:04 UTCEPSS rescore
  8. 2026-08-19 09:12 UTCGHSA enrichment
  9. 2026-08-18 20:30 UTCEG score recompute
  10. 2026-08-18 20:30 UTCGHSA enrichment
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-18 13:49 UTCEPSS rescore
  13. 2026-08-18 07:48 UTCGHSA enrichment
  14. 2026-08-17 19:06 UTCEG score recompute
  15. 2026-08-17 19:06 UTCGHSA enrichment
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 06:23 UTCEG score recompute
  18. 2026-08-17 06:23 UTCGHSA enrichment
  19. 2026-08-17 05:54 UTCEG score recompute▲ 8.80
  20. 2026-08-17 05:54 UTCGHSA enrichment
  21. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 8.8 · severity → HIGH
  22. 2026-08-17 05:39 UTCEG score recompute
  23. 2026-08-17 05:39 UTCGHSA enrichment
  24. 2026-08-17 05:39 UTCMITRE cvelistV5
  25. 2026-08-16 14:56 UTCEPSS rescore
Show 4 more
  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-15 13:27 UTCNVD update
  3. 2026-08-15 12:38 UTCEG score recompute
  4. 2026-08-15 12:37 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-74561?
CVE-2026-74561 is a high vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: nexthop: avoid unlocked f6ilist walk in nhrtcacheflush nhrtcacheflush() walks nh->f6ilist during an RTNL-serialized nexthop replace without holding nh->lock, racing the unlocked IPv6 route add/delete that mutate the list under…
When was CVE-2026-74561 disclosed?
CVE-2026-74561 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74561 actively exploited?
CVE-2026-74561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.4% of all scored CVEs.
What is the CVSS score of CVE-2026-74561?
CVE-2026-74561 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-74561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74561, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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