CVE-2026-49283

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 72% 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, secondary
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1.

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
39
EG Risk 39/100

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
Severity87% × 45%
Exploitation0% × 40%
Automatability0% × 15%
EPSS PROB
0.5%
EPSS %ILE
38th
KEV
Not listed

Published

July 2, 2026

Last Modified

September 18, 2026

Advisory Details (5)

Auto-updated Aug 19, 2026
Patch available. Sources: github, github_commit.
github_commit

commit e2df79926099 (simplesamlphp/saml2)

Fix landed in simplesamlphp/saml2 commit e2df79926099 — awaiting tagged release

https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f
github_commit

commit d5c213132ef6 (simplesamlphp/saml2)

Fix landed in simplesamlphp/saml2 commit d5c213132ef6 — awaiting tagged release

https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a
github_commit

commit a2c1ac588c70 (simplesamlphp/saml2)

Fix landed in simplesamlphp/saml2 commit a2c1ac588c70 — awaiting tagged release

https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f
github_commit Patch Available

commit 4a71b20d8d84 (simplesamlphp/saml2)

Patch available: simplesamlphp/saml2 v7.0.0-rc1 (contains commit 4a71b20d8d84)

https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d
githubMentions a patch (unverified)

SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass · Advisory · simplesamlphp/saml2 · GitHub

https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx

Vendor Advisories for CVE-2026-49283(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 3 ecosystems)
Packagist(2)
PackageVulnerable rangeFix by version rangeDependents
simplesamlphp/saml24.6.9 ... v4.6.8 (152 versions)
  • 6.0.0 up to 6.2.1: fixed in 6.2.1
  • 5.0.0 up to 5.0.6: fixed in 5.0.6
  • 4.20.0 up to 4.20.2: fixed in 4.20.2
  • every version up to 4.19.3: fixed in 4.19.3
—
simplesamlphp/saml2-legacy4.6.9 ... v4.6.8 (150 versions)
  • 4.20.0 up to 4.20.2: fixed in 4.20.2
  • every version up to 4.19.3: fixed in 4.19.3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
simplesamlphp1.19.7-1 ... 2.5.3.1-1 (10 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
simplesamlphp1.10.0-1 ... 2.5.3.1-1 (75 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× 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.

  1. 2026-10-10 20:00 UTCEPSS rescore
  2. 2026-10-09 20:07 UTCEPSS rescore
  3. 2026-10-08 17:12 UTCEPSS rescore
  4. 2026-10-07 23:48 UTCEPSS rescore
  5. 2026-10-06 15:18 UTCEPSS rescore
  6. 2026-10-05 17:43 UTCEPSS rescore
  7. 2026-10-04 23:22 UTCEPSS rescore
  8. 2026-10-03 14:25 UTCEPSS rescore
  9. 2026-10-01 19:50 UTCEPSS rescore
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-28 13:51 UTCEPSS rescore
  12. 2026-09-27 13:48 UTCEPSS rescore
  13. 2026-09-26 15:59 UTCEPSS rescore
  14. 2026-09-26 00:27 UTCEPSS rescore
  15. 2026-09-23 17:53 UTCEPSS rescore
  16. 2026-09-23 06:38 UTCEG score recompute
  17. 2026-09-20 20:16 UTCEPSS rescore
  18. 2026-09-18 20:35 UTCEG score recompute
  19. 2026-09-18 19:28 UTCEPSS rescore
  20. 2026-09-18 06:14 UTCEG score recompute
  21. 2026-09-16 14:08 UTCEPSS rescore
  22. 2026-09-16 05:15 UTCEPSS rescore
  23. 2026-09-14 00:15 UTCEG score recompute
  24. 2026-09-13 16:47 UTCEPSS rescore
  25. 2026-09-13 08:59 UTCEG score recompute
Show 35 more
  1. 2026-09-12 14:15 UTCEG score recompute
  2. 2026-09-11 14:53 UTCEPSS rescore
  3. 2026-09-10 09:35 UTCEPSS rescore
  4. 2026-09-08 22:01 UTCEPSS rescore
  5. 2026-09-07 16:01 UTCEPSS rescore
  6. 2026-09-06 14:19 UTCEG score recompute
  7. 2026-09-06 13:47 UTCEPSS rescore
  8. 2026-09-05 23:52 UTCEG score recompute
  9. 2026-09-04 05:06 UTCEPSS rescore
  10. 2026-09-02 14:12 UTCEPSS rescore
  11. 2026-09-01 13:54 UTCEPSS rescore
  12. 2026-09-01 04:40 UTCEPSS rescore
  13. 2026-08-30 22:20 UTCEG score recompute
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 11:22 UTCEG score recompute
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-28 21:41 UTCEPSS rescore
  18. 2026-08-27 22:14 UTCEG score recompute
  19. 2026-08-27 14:25 UTCEPSS rescore
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-24 15:05 UTCEG score recompute
  23. 2026-08-23 06:20 UTCEG score recompute
  24. 2026-08-23 00:19 UTCEPSS rescore
  25. 2026-08-22 06:26 UTCEG score recompute
  26. 2026-08-21 23:49 UTCEPSS rescore
  27. 2026-08-21 04:27 UTCEG score recompute
  28. 2026-08-20 22:55 UTCEPSS rescore
  29. 2026-08-19 19:21 UTCEG score recompute
  30. 2026-08-19 18:23 UTCEG score recompute
  31. 2026-08-19 15:31 UTCEG score recompute
  32. 2026-07-30 17:18 UTCEG score recompute
  33. 2026-07-26 13:02 UTCEG score recompute
  34. 2026-07-23 03:18 UTCEG score recompute
  35. 2026-07-02 21:07 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-49283?
CVE-2026-49283 is a high vulnerability published on July 2, 2026. The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider.…
When was CVE-2026-49283 disclosed?
CVE-2026-49283 was first published on July 2, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49283 actively exploited?
CVE-2026-49283 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (38th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-49283?
CVE-2026-49283 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-49283?
A fix for CVE-2026-49283 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-49283 are linked in the Vendor Advisories panel on this page.

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