CVE-2026-123542 (CVSS 6.8)

Description

OpenAM before 16.1.4 fails to enforce PKCE in the OAuth 2.0 device authorization flow, never validating the code verifier when device codes are exchanged for tokens. Attackers who obtain an approved device code from client logs or shared device storage can redeem it for access and ID tokens to impersonate the user.

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CVSS v3.1 Score

6.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-358 CWE-358

References

Other References

https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-h93p-35jm-rj83 https://www.vulncheck.com/advisories/openam-before-16.1.4-pkce-bypass-in-oauth-2.0-device-authorization-flow

Frequently Asked Questions

What is CVE-2026-123542? +

OpenAM before 16.1.4 fails to enforce PKCE in the OAuth 2.0 device authorization flow, never validating the code verifier when device codes are exchanged for tokens. Attackers who obtain an approved device code from client logs or shared device storage can redeem it for access and ID tokens to impersonate the user. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2026-123542? +

CVE-2026-123542 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-123542? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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