CVE-2026-77641

HIGHNVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0

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

tor before 0.4.9.9 was prone to a NULL write after free when sending a CONFLUX_SWITCH cell fails. The return value of relay_send_command_from_edge() was ignored, so a send failure (which calls circuit_mark_for_close() and removes the leg via cfx_del_leg()) would go undetected, causing the caller to write to the now-freed current leg and resulting in a crash. This is TROVE-2026-017.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 8, 2026

References (1)

Vendor Advisories for CVE-2026-77641(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
tor0.4.7.13-1 ... 0.4.9.9-1~bpo13+1 (46 versions)0.4.9.9-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
tor0.4.8.16-1 ... 0.4.9.9-1~bpo13+1 (22 versions)0.4.9.11-0+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
tor0.4.8.16-1 ... 0.4.9.9-1~bpo13+1 (19 versions)0.4.9.9-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 27× in last 7d / 95× 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. 2026-09-18 23:07 UTCEG score recompute
  2. 2026-09-18 23:07 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 11:39 UTCGHSA enrichment
  5. 2026-09-18 00:07 UTCEG score recompute
  6. 2026-09-18 00:07 UTCGHSA enrichment
  7. 2026-09-17 11:11 UTCGHSA enrichment
  8. 2026-09-16 23:44 UTCEG score recompute
  9. 2026-09-16 23:44 UTCGHSA enrichment
  10. 2026-09-16 14:08 UTCEPSS rescore
  11. 2026-09-16 12:16 UTCEG score recompute
  12. 2026-09-16 12:16 UTCGHSA enrichment
  13. 2026-09-16 05:15 UTCEPSS rescore
  14. 2026-09-16 00:49 UTCGHSA enrichment
  15. 2026-09-15 13:12 UTCEG score recompute
  16. 2026-09-15 13:12 UTCGHSA enrichment
  17. 2026-09-15 03:12 UTCEPSS rescore
  18. 2026-09-15 03:12 UTCEPSS rescore
  19. 2026-09-15 01:44 UTCGHSA enrichment
  20. 2026-09-14 14:17 UTCGHSA enrichment
  21. 2026-09-14 02:50 UTCEG score recompute
  22. 2026-09-14 02:50 UTCGHSA enrichment
  23. 2026-09-13 15:23 UTCGHSA enrichment
  24. 2026-09-13 03:56 UTCGHSA enrichment
  25. 2026-09-12 16:28 UTCEG score recompute
Show 70 more
  1. 2026-09-12 16:28 UTCGHSA enrichment
  2. 2026-09-12 15:02 UTCEPSS rescore
  3. 2026-09-12 05:01 UTCGHSA enrichment
  4. 2026-09-11 17:33 UTCEG score recompute
  5. 2026-09-11 17:33 UTCGHSA enrichment
  6. 2026-09-11 14:53 UTCEPSS rescore
  7. 2026-09-11 05:22 UTCGHSA enrichment
  8. 2026-09-10 17:54 UTCEG score recompute
  9. 2026-09-10 17:54 UTCGHSA enrichment
  10. 2026-09-10 09:35 UTCEPSS rescore
  11. 2026-09-10 06:27 UTCGHSA enrichment
  12. 2026-09-09 19:00 UTCGHSA enrichment
  13. 2026-09-09 07:32 UTCEG score recompute
  14. 2026-09-09 07:32 UTCGHSA enrichment
  15. 2026-09-08 22:01 UTCEPSS rescore
  16. 2026-09-08 20:05 UTCEG score recompute▲ 1.70
  17. 2026-09-08 20:05 UTCGHSA enrichment
  18. 2026-09-08 18:29 UTCNVD updateCVSS v3 → 8.2 · severity → HIGH
  19. 2026-09-08 08:05 UTCEG score recompute
  20. 2026-09-08 08:05 UTCGHSA enrichment
  21. 2026-09-07 10:00 UTCEG score recompute
  22. 2026-09-07 10:00 UTCGHSA enrichment
  23. 2026-09-06 13:48 UTCEPSS rescore
  24. 2026-09-06 11:55 UTCEG score recompute
  25. 2026-09-06 11:55 UTCGHSA enrichment
  26. 2026-09-05 13:50 UTCGHSA enrichment
  27. 2026-09-04 15:43 UTCEG score recompute
  28. 2026-09-04 15:43 UTCGHSA enrichment
  29. 2026-09-04 05:07 UTCEPSS rescore
  30. 2026-09-03 17:39 UTCGHSA enrichment
  31. 2026-09-03 06:50 UTCEG score recompute
  32. 2026-09-03 06:50 UTCGHSA enrichment
  33. 2026-09-02 14:12 UTCEPSS rescore
  34. 2026-09-02 08:45 UTCEG score recompute
  35. 2026-09-02 08:45 UTCGHSA enrichment
  36. 2026-09-01 13:54 UTCEPSS rescore
  37. 2026-09-01 10:40 UTCGHSA enrichment
  38. 2026-08-31 12:35 UTCEG score recompute
  39. 2026-08-31 12:35 UTCGHSA enrichment
  40. 2026-08-30 19:18 UTCEPSS rescore
  41. 2026-08-30 19:17 UTCEPSS rescore
  42. 2026-08-30 14:19 UTCEG score recompute
  43. 2026-08-30 14:19 UTCGHSA enrichment
  44. 2026-08-30 01:22 UTCEPSS rescore
  45. 2026-08-29 16:14 UTCEG score recompute
  46. 2026-08-29 16:14 UTCGHSA enrichment
  47. 2026-08-28 21:42 UTCEPSS rescore
  48. 2026-08-28 18:06 UTCGHSA enrichment
  49. 2026-08-27 17:37 UTCEG score recompute
  50. 2026-08-27 17:37 UTCGHSA enrichment
  51. 2026-08-27 17:17 UTCEG score recompute
  52. 2026-08-27 17:17 UTCGHSA enrichment
  53. 2026-08-27 07:53 UTCEG score recompute
  54. 2026-08-27 07:53 UTCGHSA enrichment
  55. 2026-08-26 14:47 UTCEPSS rescore
  56. 2026-08-26 09:49 UTCGHSA enrichment
  57. 2026-08-25 11:43 UTCEG score recompute
  58. 2026-08-25 11:43 UTCGHSA enrichment
  59. 2026-08-24 14:18 UTCEPSS rescore
  60. 2026-08-24 13:38 UTCEG score recompute
  61. 2026-08-24 13:38 UTCGHSA enrichment
  62. 2026-08-23 15:33 UTCGHSA enrichment
  63. 2026-08-22 17:30 UTCEG score recompute
  64. 2026-08-22 17:30 UTCGHSA enrichment
  65. 2026-08-21 23:49 UTCEPSS rescore
  66. 2026-08-21 19:26 UTCEG score recompute
  67. 2026-08-21 19:26 UTCGHSA enrichment
  68. 2026-08-20 21:22 UTCEG score recompute
  69. 2026-08-20 21:17 UTCEG score recompute
  70. 2026-08-20 21:16 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77641?
CVE-2026-77641 is a high vulnerability published on August 20, 2026. tor before 0.4.9.9 was prone to a NULL write after free when sending a CONFLUXSWITCH cell fails. The return value of relaysendcommandfromedge() was ignored, so a send failure (which calls circuitmarkforclose() and removes the leg via cfxdelleg()) would go undetected, causing the caller to write to…
When was CVE-2026-77641 disclosed?
CVE-2026-77641 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77641 actively exploited?
CVE-2026-77641 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 89.6% of all scored CVEs.
What is the CVSS score of CVE-2026-77641?
CVE-2026-77641 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-77641?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77641, 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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