CVE-2015-1793

HIGHNVD 6.57.9▲
EchelonGraph scoreHIGH confidence

Score elevated to 7.9 because EPSS predicts 62% probability of exploitation within the next 30 days (top 0.9% of all CVEs). NVD baseline CVSS 6.5 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Weaponized
7.9EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 62%
  • Public exploit code is available (Metasploit, epss top5pct, epss high, public exploit)
CISA-KEV: Not listedEPSS PROB: 62%CVSS: 6.5Exploit: Metasploit · epss top5pct · epss high · public exploitExposed: 0

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

The X509_verify_cert function in crypto/x509/x509_vfy.c in OpenSSL 1.0.1n, 1.0.1o, 1.0.2b, and 1.0.2c does not properly process X.509 Basic Constraints cA values during identification of alternative certificate chains, which allows remote attackers to spoof a Certification Authority role and trigger unintended certificate verifications via a valid leaf certificate.

CVSS v3
6.5
EG Score
7.9(high)
EG Risk
66(Track)
EG Risk 66/100SSVC: 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
Severity79% × 45%
Exploitation65% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
62%
EPSS %ILE
99%
KEV
Not listed

Published

July 9, 2015

Last Modified

May 6, 2026

References (62)

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
openssl—1.0.2d-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
openssl—1.0.2d-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
openssl—1.0.2d-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
openssl—1.0.2d-1—

Data Freshness Timeline

(refreshed 5× in last 7d / 21× 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 22:50 UTCEPSS rescore
  2. 2026-08-19 16:59 UTCEPSS rescore
  3. 2026-08-18 13:43 UTCEPSS rescore
  4. 2026-08-16 02:09 UTCEPSS rescore
  5. 2026-08-15 01:25 UTCEPSS rescore
  6. 2026-08-14 19:24 UTCOSV refresh
  7. 2026-08-12 13:46 UTCEPSS rescore
  8. 2026-08-08 16:31 UTCEPSS rescore
  9. 2026-08-06 13:42 UTCEPSS rescore
  10. 2026-08-05 19:12 UTCEPSS rescore
  11. 2026-08-02 02:22 UTCEPSS rescore
  12. 2026-08-01 04:11 UTCEPSS rescore
  13. 2026-07-30 16:23 UTCEPSS rescore
  14. 2026-07-30 07:54 UTCOSV refresh
  15. 2026-07-30 01:26 UTCEPSS rescore
  16. 2026-07-28 15:31 UTCEPSS rescore
  17. 2026-07-26 14:50 UTCEPSS rescore
  18. 2026-07-24 14:13 UTCEPSS rescore
  19. 2026-07-23 14:14 UTCEPSS rescore
  20. 2026-07-23 01:16 UTCEG score recompute
  21. 2026-07-23 00:19 UTCEG score recompute▲ 1.40
  22. 2026-07-22 21:57 UTCEG score recompute
  23. 2026-07-22 14:04 UTCEPSS rescore
  24. 2026-07-21 15:21 UTCEPSS rescore
  25. 2026-07-21 15:21 UTCEPSS rescore
Show 68 more
  1. 2026-07-20 17:03 UTCEPSS rescore
  2. 2026-07-19 02:26 UTCEPSS rescore
  3. 2026-07-19 02:26 UTCEPSS rescore
  4. 2026-07-18 10:00 UTCEPSS rescore
  5. 2026-07-15 16:54 UTCEPSS rescore
  6. 2026-07-15 16:54 UTCEPSS rescore
  7. 2026-07-13 22:26 UTCEPSS rescore
  8. 2026-07-12 16:38 UTCOSV refresh
  9. 2026-07-12 05:42 UTCEPSS rescore
  10. 2026-07-11 08:23 UTCEPSS rescore
  11. 2026-07-09 19:05 UTCEPSS rescore
  12. 2026-07-08 15:10 UTCEPSS rescore
  13. 2026-07-06 16:24 UTCEPSS rescore
  14. 2026-07-05 02:26 UTCEPSS rescore
  15. 2026-07-04 06:27 UTCEPSS rescore
  16. 2026-07-02 15:21 UTCEPSS rescore
  17. 2026-07-01 15:02 UTCEPSS rescore
  18. 2026-07-01 15:02 UTCEPSS rescore
  19. 2026-06-28 04:53 UTCEPSS rescore
  20. 2026-06-27 03:05 UTCEPSS rescore
  21. 2026-06-25 13:47 UTCEPSS rescore
  22. 2026-06-25 13:47 UTCEPSS rescore
  23. 2026-06-23 22:29 UTCOSV refresh
  24. 2026-06-23 21:30 UTCEPSS rescore
  25. 2026-06-22 14:23 UTCEPSS rescore
  26. 2026-06-22 14:22 UTCEPSS rescore
  27. 2026-06-21 01:57 UTCEPSS rescore
  28. 2026-06-21 01:57 UTCEPSS rescore
  29. 2026-06-18 17:50 UTCEPSS rescore
  30. 2026-06-18 17:49 UTCEPSS rescore
  31. 2026-06-17 17:49 UTCEPSS rescore
  32. 2026-06-16 17:50 UTCEPSS rescore
  33. 2026-06-16 17:49 UTCEPSS rescore
  34. 2026-06-15 17:45 UTCEPSS rescore
  35. 2026-06-13 22:57 UTCEPSS rescore
  36. 2026-06-12 23:09 UTCEPSS rescore
  37. 2026-06-11 13:57 UTCEPSS rescore
  38. 2026-06-10 22:15 UTCEPSS rescore
  39. 2026-06-08 14:14 UTCEPSS rescore
  40. 2026-06-07 15:22 UTCEPSS rescore
  41. 2026-06-07 06:23 UTCOSV refresh
  42. 2026-06-06 13:45 UTCEPSS rescore
  43. 2026-06-05 22:44 UTCEPSS rescore
  44. 2026-06-05 06:08 UTCEPSS rescore
  45. 2026-06-05 06:08 UTCEPSS rescore
  46. 2026-06-02 20:10 UTCEPSS rescore
  47. 2026-06-02 20:10 UTCEPSS rescore
  48. 2026-06-01 13:49 UTCEPSS rescore
  49. 2026-06-01 13:49 UTCEPSS rescore
  50. 2026-05-31 22:28 UTCEPSS rescore
  51. 2026-05-31 22:28 UTCEPSS rescore
  52. 2026-05-31 22:28 UTCEPSS rescore
  53. 2026-05-31 00:14 UTCEPSS rescore
  54. 2026-05-29 13:41 UTCEPSS rescore
  55. 2026-05-28 13:42 UTCEPSS rescore
  56. 2026-05-28 13:42 UTCEPSS rescore
  57. 2026-05-27 13:38 UTCEPSS rescore
  58. 2026-05-27 13:38 UTCEPSS rescore
  59. 2026-05-26 07:16 UTCEPSS rescore
  60. 2026-05-26 07:16 UTCEPSS rescore
  61. 2026-05-23 15:10 UTCEPSS rescore
  62. 2026-05-23 00:42 UTCEG score recompute
  63. 2026-05-23 00:41 UTCGHSA enrichment
  64. 2026-05-22 21:15 UTCEPSS rescore
  65. 2026-05-22 21:15 UTCEPSS rescore
  66. 2026-05-22 14:43 UTCOSV refresh
  67. 2026-05-18 21:30 UTCEPSS rescore
  68. 2026-05-18 21:30 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-38640
    First seen Nov 5, 2015

    OpenSSL - Alternative Chains Certificate Forgery

    Open source ↗
  • Metasploitauxiliary/server/openssl_altchainsforgery_mitm_proxy✓ verified
    First seen Jul 9, 2015

    OpenSSL Alternative Chains Certificate Forgery MITM Proxy

    Open source ↗

Frequently asked(5)

What is CVE-2015-1793?
CVE-2015-1793 is a high vulnerability published on July 9, 2015. The X509verifycert function in crypto/x509/x509_vfy.c in OpenSSL 1.0.1n, 1.0.1o, 1.0.2b, and 1.0.2c does not properly process X.509 Basic Constraints cA values during identification of alternative certificate chains, which allows remote attackers to spoof a Certification Authority role and trigger…
When was CVE-2015-1793 disclosed?
CVE-2015-1793 was first published in the National Vulnerability Database on July 9, 2015, with the most recent update on May 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2015-1793 actively exploited?
CVE-2015-1793 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 62% probability of exploitation in the next 30 days, which ranks it in the top 0.9% of all scored CVEs.
What is the CVSS score of CVE-2015-1793?
CVE-2015-1793 has a CVSS v3 base score of 6.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.9.
How do I remediate CVE-2015-1793?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2015-1793, 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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