CVE-2026-77638

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under NVD CVSS v3. EPSS exploit probability: 0.3% (20th percentile of EPSS-scored CVEs). GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 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: 0.3%CVSS: 9.0Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.0CRITICALmedium confidence
EG Risk
41
EG Risk 41/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
20th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 rangeFix by version rangeDependents
tor0.4.7.13-1 ... 0.4.9.9-1~bpo13+1 (47 versions)
  • every version up to 0.4.9.11-0+deb12u1: fixed in 0.4.9.11-0+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
tor0.4.8.16-1 ... 0.4.9.9-1~bpo13+1 (22 versions)
  • every version up to 0.4.9.11-0+deb13u1: fixed in 0.4.9.11-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
tor0.4.8.16-1 ... 0.4.9.9-1~bpo13+1 (21 versions)
  • every version up to 0.4.9.11-1: fixed in 0.4.9.11-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 40× in last 7d / 165× 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 225 total refreshes for this CVE.

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

Related CVEs(same product + 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 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 0.3% probability of exploitation in the next 30 days (20th percentile of EPSS-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?
A fix for CVE-2026-77638 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77638 are linked in the Vendor Advisories panel on this page.

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