CVE-2026-55785

LOWCVSS 3.7/10EPSS 0.28%

Last modified

CVE-2026-55785 is a low-severity vulnerability rated 3.7/10 on the CVSS scale. 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. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.28%

20.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
free5gcfree5gc< 1.4.5

References

Timeline

Published
Last Modified
Status
Deferred

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.
How severe is CVE-2026-55785?
CVE-2026-55785 has a CVSS score of 3.7/10 (LOW severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2026-55785?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST