CVE-2026-55785

LOW
Published Aug 28, 2026 Modified Aug 31, 2026 CWE-208 CWE-385 CWE-532

Description

free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the AUSF component performs cryptographic authentication comparisons in internal/sbi/processor/ue_authentication.go with ordinary equality helpers. Auth5gAkaComfirmRequestProcedure compares RES* and XRES* with strings.EqualFold and logs the expected XRES* value at INFO level before comparison. EapAuthComfirmRequestProcedure compares AT_MAC and XMAC with bytes.Equal and evaluates XRES == RES with ordinary string equality. These comparisons can return at mismatch-dependent times, although testing did not demonstrate a practical remote timing oracle because of HTTP/SBI timing noise. The INFO log exposes authentication material to operators, log collectors, sidecars, or processes able to read AUSF logs. This issue is fixed in version 1.4.5.

Is your site exposed to CVE-2026-55785?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

3.7
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0028
Probability of exploitation
0.21%
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-208 CWE-208
CWE-385 CWE-385
CWE-532 CWE-532

References

Frequently Asked Questions

What is CVE-2026-55785? +
free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the AUSF component performs cryptographic authentication comparisons in internal/sbi/processor/ue_authentication.go with ordinary equality helpers. Auth5gAkaComfirmRequestProcedure compares RES* and XRES* with strings.EqualFold and logs the expected XRES* value at INFO level before comparison. EapAuthComfirmRequestProcedure compares AT_MAC and XMAC with bytes.Equal and evaluates XRES == RES with ordinary string equality. These comparisons can return at mismatch-dependent times, although testing did not demonstrate a practical remote timing oracle because of HTTP/SBI timing noise. The INFO log exposes authentication material to operators, log collectors, sidecars, or processes able to read AUSF logs. This issue is fixed in version 1.4.5. It has a CVSS v3.1 base score of 3.7 (LOW).
How severe is CVE-2026-55785? +
CVE-2026-55785 has a CVSS v3.1 score of 3.7 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-55785? +
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.

Related Vulnerabilities

CVE-2026-8794

PaperCut NG/MF contains an observable timing discrepancy in its authentication component. An unauthenticated remote attacker can exploit this vulnerability to …
CVE-2025-29780

Post-Quantum Secure Feldman's Verifiable Secret Sharing provides a Python implementation of Feldman's Verifiable Secret Sharing (VSS) scheme. In versions 0.8.0b2 …
CVE-2025-48995

SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned …
CVE-2025-53940

Quiet is an alternative to team chat apps like Slack, Discord, and Element that does not require trusting a central …
CVE-2025-7071

Padding oracle attack vulnerability in Oberon microsystem AG’s ocrypto library in all versions since 3.1.0 and prior to 3.9.2 allows …
CVE-2025-7383

Padding oracle attack vulnerability in Oberon microsystem AG’s Oberon PSA Crypto library in all versions since 1.0.0 and prior to …

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-55785 — free, no signup required.