CVE-2026-56016

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

Score 5.9 from GitHub Security Advisory published 2026-07-01. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.9Exploit: None knownExposed: 0

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

CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources.

The generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID is drawn from a small range, the epoch time can be guessed or read from the HTTP Date header, and Perl's rand() is unsuitable for security purposes because it is predictable and reversible.

An attacker who predicts a session id can impersonate the corresponding session and bypass authentication.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
31(Track)
EG Risk 31/100SSVC: 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
Severity59% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
41%
KEV
Not listed

Published

July 1, 2026

Last Modified

July 2, 2026

Advisory Details (3)

Auto-updated Jul 5, 2026
No patch confirmed yet.
generic

oss-security - CVE-2026-56016: CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources

http://www.openwall.com/lists/oss-security/2026/07/01/6
generic

lib/CGI/Session/ID/md5.pm - metacpan.org

https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/source/lib/CGI/Session/ID/md5.pm
generic

Changes - metacpan.org

https://metacpan.org/release/MARKSTOS/CGI-Session-4.49/changes

Vendor Advisories for CVE-2026-56016(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 5 ecosystems)
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
perl-cgi-session—4.49-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
libcgi-session-perl4.48-3, 4.48-4, 4.49-1——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libcgi-session-perl4.48-4, 4.49-1——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libcgi-session-perl4.48-4, 4.49-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libcgi-session-perl4.48-44.49-1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 81× 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 134 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-56016?
CVE-2026-56016 is a medium vulnerability published on July 1, 2026. CGI::Session::ID::md5 versions before 4.49 for Perl generate predictable session ids from low-entropy sources. The generate_id method builds the session id from a MD5 digest of the process id, the epoch time, and the built-in rand() function. All three are predictable, low-entropy sources: the PID…
When was CVE-2026-56016 disclosed?
CVE-2026-56016 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56016 actively exploited?
CVE-2026-56016 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 58.6% of all scored CVEs.
What is the CVSS score of CVE-2026-56016?
CVE-2026-56016 has a CVSS v3.1 base score of 5.9 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-56016?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56016, 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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