CVE-2025-27773

HIGHNVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 78% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: Elevated riskExposed: 0

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

The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: Attend

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
Severity86% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

March 11, 2025

Last Modified

April 15, 2026

Advisory Details (5)

Auto-updated Sep 1, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
generic Patch Available

[SECURITY] [DLA 4161-1] simplesamlphp security update

https://lists.debian.org/debian-lts-announce/2025/05/msg00013.html
github Patch Available🟡 PoC Available

Incorrect signature verification for HTTP-Redirect binding · Advisory · simplesamlphp/saml2 · GitHub

https://github.com/simplesamlphp/saml2/security/advisories/GHSA-46r4-f8gj-xg56
github_commit Patch Available

commit 7867d6099dc7 (simplesamlphp/saml2)

Patch available: simplesamlphp/saml2 v6.0.0 (contains commit 7867d6099dc7)

https://github.com/simplesamlphp/saml2/commit/7867d6099dc7f31bed1ea10e5bea159c5623d2a0
generic

saml2/src/SAML2/HTTPRedirect.php at 9545abd0d9d48388f2fa00469c5c1e0294f0303e · simplesamlphp/saml2 · GitHub

https://github.com/simplesamlphp/saml2/blob/9545abd0d9d48388f2fa00469c5c1e0294f0303e/src/SAML2/HTTPRedirect.php#L178-L217
generic

saml2/src/SAML2/HTTPRedirect.php at 9545abd0d9d48388f2fa00469c5c1e0294f0303e · simplesamlphp/saml2 · GitHub

https://github.com/simplesamlphp/saml2/blob/9545abd0d9d48388f2fa00469c5c1e0294f0303e/src/SAML2/HTTPRedirect.php#L104-L113

Affected Packages

(5 across 4 ecosystems)
Packagist(2)
PackageVulnerable rangeFixed inDependents
simplesamlphp/saml2v5.0.0-alpha.1 ... v5.0.0-alpha3 (19 versions)5.0.0-alpha.20—
simplesamlphp/saml2-legacy4.6.9 ... v4.6.8 (144 versions)4.17.0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
simplesamlphp1.19.0-1, 1.19.0-1+deb11u11.19.0-1+deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
simplesamlphp1.19.7-1, 1.19.7-1+deb12u11.19.7-1+deb12u2—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
simplesamlphp1.10.0-1 ... 1.9.2-1 (68 versions)1.19.7-2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 27× 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 180 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2025-27773?
CVE-2025-27773 is a high vulnerability published on March 11, 2025. The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to…
When was CVE-2025-27773 disclosed?
CVE-2025-27773 was first published in the National Vulnerability Database on March 11, 2025, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-27773 actively exploited?
CVE-2025-27773 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 67.3% of all scored CVEs.
What is the CVSS score of CVE-2025-27773?
CVE-2025-27773 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2025-27773?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-27773, 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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