CVE-2026-77638

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 91% 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 — 4 sources updated this week
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.0Exploit: None knownExposed: 0

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

Tor before 0.4.9.11 is prone to a race condition where in just the right circumstances a rendezvous point could man-in-the-middle (impersonate) the onion service that the client was trying to reach.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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
Severity90% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 16, 2026

References (1)

Vendor Advisories for CVE-2026-77638(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 (47 versions)0.4.9.11-0+deb12u1—
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 (21 versions)0.4.9.11-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 42× in last 7d / 126× 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 131 total refreshes for this CVE.

  1. 2026-09-20 13:29 UTCGHSA enrichment
  2. 2026-09-20 08:58 UTCGHSA enrichment
  3. 2026-09-20 02:38 UTCGHSA enrichment
  4. 2026-09-19 22:37 UTCGHSA enrichment
  5. 2026-09-19 18:28 UTCEG score recompute
  6. 2026-09-19 18:27 UTCGHSA enrichment
  7. 2026-09-19 14:18 UTCGHSA enrichment
  8. 2026-09-19 10:11 UTCGHSA enrichment
  9. 2026-09-19 05:42 UTCGHSA enrichment
  10. 2026-09-19 01:40 UTCGHSA enrichment
  11. 2026-09-18 21:38 UTCEG score recompute
  12. 2026-09-18 21:38 UTCGHSA enrichment
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-18 17:28 UTCGHSA enrichment
  15. 2026-09-18 13:26 UTCGHSA enrichment
  16. 2026-09-18 09:25 UTCGHSA enrichment
  17. 2026-09-18 05:22 UTCGHSA enrichment
  18. 2026-09-18 01:20 UTCGHSA enrichment
  19. 2026-09-17 21:19 UTCEG score recompute
  20. 2026-09-17 21:19 UTCGHSA enrichment
  21. 2026-09-17 15:51 UTCGHSA enrichment
  22. 2026-09-17 11:50 UTCGHSA enrichment
  23. 2026-09-17 07:48 UTCGHSA enrichment
  24. 2026-09-17 03:47 UTCGHSA enrichment
  25. 2026-09-16 23:46 UTCGHSA enrichment
Show 75 more
  1. 2026-09-16 19:44 UTCGHSA enrichment
  2. 2026-09-16 14:16 UTCEG score recompute▲ 0.10
  3. 2026-09-16 14:16 UTCGHSA enrichment
  4. 2026-09-16 14:16 UTCNVD updateCVSS v3 → 9 · severity → CRITICAL
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 06:05 UTCEG score recompute
  7. 2026-09-16 06:05 UTCGHSA enrichment
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-15 18:47 UTCGHSA enrichment
  10. 2026-09-15 07:00 UTCEG score recompute
  11. 2026-09-15 07:00 UTCGHSA enrichment
  12. 2026-09-15 03:12 UTCEPSS rescore
  13. 2026-09-15 03:12 UTCEPSS rescore
  14. 2026-09-14 19:43 UTCGHSA enrichment
  15. 2026-09-14 08:26 UTCGHSA enrichment
  16. 2026-09-13 21:09 UTCEG score recompute
  17. 2026-09-13 21:09 UTCGHSA enrichment
  18. 2026-09-13 09:52 UTCGHSA enrichment
  19. 2026-09-12 22:35 UTCEG score recompute
  20. 2026-09-12 22:35 UTCGHSA enrichment
  21. 2026-09-12 15:02 UTCEPSS rescore
  22. 2026-09-12 11:18 UTCGHSA enrichment
  23. 2026-09-11 23:28 UTCEG score recompute
  24. 2026-09-11 23:28 UTCGHSA enrichment
  25. 2026-09-11 14:53 UTCEPSS rescore
  26. 2026-09-11 12:10 UTCEG score recompute
  27. 2026-09-11 12:10 UTCGHSA enrichment
  28. 2026-09-11 00:18 UTCGHSA enrichment
  29. 2026-09-10 12:14 UTCEG score recompute
  30. 2026-09-10 12:14 UTCGHSA enrichment
  31. 2026-09-10 09:35 UTCEPSS rescore
  32. 2026-09-10 00:48 UTCGHSA enrichment
  33. 2026-09-09 13:13 UTCGHSA enrichment
  34. 2026-09-09 01:54 UTCEG score recompute
  35. 2026-09-09 01:54 UTCGHSA enrichment
  36. 2026-09-08 22:01 UTCEPSS rescore
  37. 2026-09-08 02:48 UTCEG score recompute
  38. 2026-09-08 02:48 UTCGHSA enrichment
  39. 2026-09-07 15:32 UTCGHSA enrichment
  40. 2026-09-07 00:59 UTCEG score recompute
  41. 2026-09-07 00:59 UTCGHSA enrichment
  42. 2026-09-06 13:48 UTCEPSS rescore
  43. 2026-09-06 13:30 UTCGHSA enrichment
  44. 2026-09-06 02:13 UTCEG score recompute
  45. 2026-09-06 02:13 UTCGHSA enrichment
  46. 2026-09-05 14:56 UTCGHSA enrichment
  47. 2026-09-05 03:39 UTCGHSA enrichment
  48. 2026-09-04 16:22 UTCEG score recompute
  49. 2026-09-04 16:21 UTCGHSA enrichment
  50. 2026-09-04 05:07 UTCEPSS rescore
  51. 2026-09-04 05:05 UTCGHSA enrichment
  52. 2026-09-03 17:39 UTCGHSA enrichment
  53. 2026-09-03 10:44 UTCGHSA enrichment
  54. 2026-09-02 23:22 UTCGHSA enrichment
  55. 2026-09-02 12:04 UTCGHSA enrichment
  56. 2026-09-02 00:47 UTCGHSA enrichment
  57. 2026-09-01 13:30 UTCGHSA enrichment
  58. 2026-09-01 02:13 UTCGHSA enrichment
  59. 2026-08-31 14:48 UTCGHSA enrichment
  60. 2026-08-31 03:32 UTCEG score recompute
  61. 2026-08-31 03:31 UTCGHSA enrichment
  62. 2026-08-30 19:18 UTCEPSS rescore
  63. 2026-08-30 19:17 UTCEPSS rescore
  64. 2026-08-30 16:15 UTCGHSA enrichment
  65. 2026-08-30 04:58 UTCEG score recompute
  66. 2026-08-30 04:58 UTCGHSA enrichment
  67. 2026-08-30 01:22 UTCEPSS rescore
  68. 2026-08-29 17:41 UTCGHSA enrichment
  69. 2026-08-29 05:23 UTCEG score recompute
  70. 2026-08-29 05:22 UTCGHSA enrichment
  71. 2026-08-28 21:42 UTCEPSS rescore
  72. 2026-08-28 18:06 UTCGHSA enrichment
  73. 2026-08-28 04:55 UTCGHSA enrichment
  74. 2026-08-27 17:38 UTCEG score recompute
  75. 2026-08-27 17:37 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77638?
CVE-2026-77638 is a critical vulnerability published on August 20, 2026. Tor before 0.4.9.11 is prone to a race condition where in just the right circumstances a rendezvous point could man-in-the-middle (impersonate) the onion service that the client was trying to reach.
When was CVE-2026-77638 disclosed?
CVE-2026-77638 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77638 actively exploited?
CVE-2026-77638 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 90.8% of all scored CVEs.
What is the CVSS score of CVE-2026-77638?
CVE-2026-77638 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2026-77638?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77638, 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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