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 73% 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%CVSS: 8.7Exploit: None knownExposed: 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 4.19.3, 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
8.7(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity87% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
27%
KEV
Not listed

Published

July 2, 2026

Last Modified

August 19, 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
github Patch Available

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

(2 across 1 ecosystem)
Packagist(2)
PackageVulnerable rangeFixed inDependents
simplesamlphp/saml24.6.9 ... v4.6.8 (152 versions)4.19.3—
simplesamlphp/saml2-legacy4.6.9 ... v4.6.8 (150 versions)4.19.3—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 13× 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. 2026-08-26 14:46 UTCEPSS rescore
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 15:05 UTCEG score recompute
  4. 2026-08-23 06:20 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-22 06:26 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 04:27 UTCEG score recompute
  9. 2026-08-20 22:55 UTCEPSS rescore
  10. 2026-08-19 19:21 UTCEG score recompute
  11. 2026-08-19 18:23 UTCEG score recompute
  12. 2026-08-19 15:31 UTCEG score recompute
  13. 2026-07-30 17:18 UTCEG score recompute
  14. 2026-07-26 13:02 UTCEG score recompute
  15. 2026-07-23 03:18 UTCEG score recompute
  16. 2026-07-02 21:07 UTCEG score recompute

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 in the National Vulnerability Database on July 2, 2026, with the most recent update on August 19, 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% probability of exploitation in the next 30 days, which ranks it in the top 73.0% of all scored CVEs.
What is the CVSS score of CVE-2026-49283?
CVE-2026-49283 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-49283?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49283, 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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