CVE-2026-64543

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-27. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: 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:

tipc: fix use-after-free of the discoverer in tipc_disc_rcv()

bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(), but tipc_disc_rcv() still dereferences b->disc in RX softirq under rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv).

L2 bearers are safe thanks to the synchronize_net() in tipc_disable_l2_media(), but the UDP bearer defers that call to the cleanup_bearer() workqueue, so the discoverer is freed with no grace period:

BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149) Read of size 8 at addr ffff88802348b728 by task poc_tipc/184 tipc_disc_rcv (net/tipc/discover.c:149) tipc_rcv (net/tipc/node.c:2126) tipc_udp_recv (net/tipc/udp_media.c:391) udp_rcv (net/ipv4/udp.c:2643) ip_local_deliver_finish (net/ipv4/ip_input.c:241) Freed by task 181: kfree (mm/slub.c:6565) bearer_disable (net/tipc/bearer.c:418) tipc_nl_bearer_disable (net/tipc/bearer.c:1001)

The bearer is freed with kfree_rcu(); free the discoverer the same way. Add an rcu_head to struct tipc_discoverer and free it and its skb from an RCU callback.

Because the RCU callback (tipc_disc_free_rcu) lives in module text, a call_rcu() that is still pending when the tipc module is unloaded would invoke a freed function. Add an rcu_barrier() to tipc_exit() after the bearer subsystem has been torn down, so all pending discoverer callbacks have run before the module text goes away.

Reachable from an unprivileged user namespace: the TIPCv2 genl family is netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

July 27, 2026

Last Modified

August 19, 2026

Advisory Details (5)

Auto-updated Jul 30, 2026
No patch confirmed yet.
generic

tipc: fix use-after-free of the discoverer in tipc_disc_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ec7d54d8cc1723921d671e3272b427c96366506f
generic

tipc: fix use-after-free of the discoverer in tipc_disc_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b65289e1c3f352a9f92c6e19713ddd647e033253
generic

tipc: fix use-after-free of the discoverer in tipc_disc_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2
generic

tipc: fix use-after-free of the discoverer in tipc_disc_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5e215bf1c47fdddf8203a0fe80a0ed594065f101
generic

tipc: fix use-after-free of the discoverer in tipc_disc_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1579342d71133da7f00daa02c75cebec7372097b

Vendor Advisories for CVE-2026-64543(1)

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

Affected Packages

(5 across 4 ecosystems)
Debian:12(2)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 7.2~rc5-1~exp1 (338 versions)——
linux-6.12—6.12.100-1~deb12u1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (500 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.96-1 (31 versions)6.12.100-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (157 versions)7.1.5-1—

Data Freshness Timeline

(refreshed 21× in last 7d / 113× 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.

Showing the most recent 100 of 128 total refreshes for this CVE.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 23:49 UTCEG score recompute
  3. 2026-08-29 23:49 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-27 23:45 UTCEG score recompute
  6. 2026-08-27 23:45 UTCGHSA enrichment
  7. 2026-08-27 11:12 UTCGHSA enrichment
  8. 2026-08-26 22:55 UTCEG score recompute
  9. 2026-08-26 22:55 UTCGHSA enrichment
  10. 2026-08-26 14:47 UTCEPSS rescore
  11. 2026-08-26 10:37 UTCGHSA enrichment
  12. 2026-08-25 20:52 UTCEG score recompute
  13. 2026-08-25 20:51 UTCGHSA enrichment
  14. 2026-08-25 13:49 UTCEPSS rescore
  15. 2026-08-25 08:34 UTCGHSA enrichment
  16. 2026-08-24 20:18 UTCEG score recompute
  17. 2026-08-24 20:18 UTCGHSA enrichment
  18. 2026-08-24 08:00 UTCGHSA enrichment
  19. 2026-08-23 19:42 UTCGHSA enrichment
  20. 2026-08-23 07:25 UTCEG score recompute
  21. 2026-08-23 07:25 UTCGHSA enrichment
  22. 2026-08-23 00:19 UTCEPSS rescore
  23. 2026-08-22 19:08 UTCGHSA enrichment
  24. 2026-08-22 06:51 UTCEG score recompute
  25. 2026-08-22 06:51 UTCGHSA enrichment
Show 75 more
  1. 2026-08-21 23:49 UTCEPSS rescore
  2. 2026-08-21 18:34 UTCGHSA enrichment
  3. 2026-08-21 06:17 UTCEG score recompute
  4. 2026-08-21 06:17 UTCGHSA enrichment
  5. 2026-08-20 22:55 UTCEPSS rescore
  6. 2026-08-20 18:00 UTCGHSA enrichment
  7. 2026-08-20 05:44 UTCGHSA enrichment
  8. 2026-08-19 17:27 UTCEG score recompute
  9. 2026-08-19 17:27 UTCGHSA enrichment
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-19 16:57 UTCEG score recompute
  12. 2026-08-19 16:57 UTCGHSA enrichment
  13. 2026-08-19 10:03 UTCGHSA enrichment
  14. 2026-08-18 21:46 UTCEG score recompute
  15. 2026-08-18 21:46 UTCGHSA enrichment
  16. 2026-08-18 13:48 UTCEPSS rescore
  17. 2026-08-18 08:48 UTCGHSA enrichment
  18. 2026-08-17 20:15 UTCEG score recompute
  19. 2026-08-17 20:15 UTCGHSA enrichment
  20. 2026-08-17 13:47 UTCEPSS rescore
  21. 2026-08-17 05:42 UTCEG score recompute
  22. 2026-08-17 05:42 UTCGHSA enrichment
  23. 2026-08-17 05:14 UTCGHSA enrichment
  24. 2026-08-16 19:52 UTCEG score recompute
  25. 2026-08-16 19:52 UTCGHSA enrichment
  26. 2026-08-16 14:56 UTCEPSS rescore
  27. 2026-08-16 07:35 UTCEG score recompute
  28. 2026-08-16 07:35 UTCGHSA enrichment
  29. 2026-08-15 19:19 UTCGHSA enrichment
  30. 2026-08-15 07:02 UTCEG score recompute
  31. 2026-08-15 07:02 UTCGHSA enrichment
  32. 2026-08-15 01:30 UTCEPSS rescore
  33. 2026-08-14 18:15 UTCGHSA enrichment
  34. 2026-08-14 05:58 UTCEG score recompute
  35. 2026-08-14 05:58 UTCGHSA enrichment
  36. 2026-08-13 22:00 UTCEPSS rescore
  37. 2026-08-13 17:41 UTCGHSA enrichment
  38. 2026-08-13 05:24 UTCGHSA enrichment
  39. 2026-08-12 17:08 UTCEG score recompute
  40. 2026-08-12 17:07 UTCGHSA enrichment
  41. 2026-08-12 13:51 UTCEPSS rescore
  42. 2026-08-12 04:50 UTCGHSA enrichment
  43. 2026-08-11 16:33 UTCEG score recompute
  44. 2026-08-11 16:33 UTCGHSA enrichment
  45. 2026-08-11 04:15 UTCEG score recompute
  46. 2026-08-11 04:15 UTCGHSA enrichment
  47. 2026-08-11 00:00 UTCEPSS rescore
  48. 2026-08-10 15:59 UTCGHSA enrichment
  49. 2026-08-10 03:42 UTCGHSA enrichment
  50. 2026-08-09 15:25 UTCEG score recompute
  51. 2026-08-09 15:25 UTCGHSA enrichment
  52. 2026-08-09 13:47 UTCEPSS rescore
  53. 2026-08-09 03:09 UTCEG score recompute
  54. 2026-08-09 03:09 UTCGHSA enrichment
  55. 2026-08-08 16:37 UTCEPSS rescore
  56. 2026-08-08 14:52 UTCGHSA enrichment
  57. 2026-08-08 02:35 UTCGHSA enrichment
  58. 2026-08-07 14:18 UTCGHSA enrichment
  59. 2026-08-07 02:01 UTCEG score recompute
  60. 2026-08-07 02:01 UTCGHSA enrichment
  61. 2026-08-06 13:47 UTCEPSS rescore
  62. 2026-08-06 13:44 UTCGHSA enrichment
  63. 2026-08-06 01:27 UTCEG score recompute
  64. 2026-08-06 01:27 UTCGHSA enrichment
  65. 2026-08-05 19:17 UTCEPSS rescore
  66. 2026-08-05 19:17 UTCEPSS rescore
  67. 2026-08-05 13:11 UTCEG score recompute
  68. 2026-08-05 13:11 UTCGHSA enrichment
  69. 2026-08-05 10:31 UTCGHSA enrichment
  70. 2026-08-04 22:13 UTCEG score recompute
  71. 2026-08-04 22:13 UTCGHSA enrichment
  72. 2026-08-04 15:10 UTCEPSS rescore
  73. 2026-08-04 10:39 UTCEPSS rescore
  74. 2026-08-04 09:57 UTCGHSA enrichment
  75. 2026-08-03 21:16 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-64543?
CVE-2026-64543 is a high vulnerability published on July 27, 2026. In the Linux kernel, the following vulnerability has been resolved: tipc: fix use-after-free of the discoverer in tipcdiscrcv() bearerdisable() frees b->disc with tipcdisc_delete()'s plain kfree(), but tipcdiscrcv() still dereferences b->disc in RX softirq under rcureadlock() (tipcudprecv ->…
When was CVE-2026-64543 disclosed?
CVE-2026-64543 was first published in the National Vulnerability Database on July 27, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64543 actively exploited?
CVE-2026-64543 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 97.5% of all scored CVEs.
What is the CVSS score of CVE-2026-64543?
CVE-2026-64543 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-64543?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64543, 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.

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