CVE-2026-55785 free5gc CVE debrief

Who should care

Defenders responsible for 5G core network security, particularly those using the free5GC AUSF component, should assess their exposure and prioritize verification and mitigation of this vulnerability.

Why it matters

The free5GC AUSF component's insecure cryptographic authentication comparisons may allow timing side-channel attacks, exposing authentication material in logs. Defenders should verify their AUSF component versions, upgrade to 1.4.5 if necessary, and implement compensating controls to mitigate risks.

• Potential timing side-channel attacks on AUSF components
• Exposure of authentication material in AUSF logs
• Need for verification of AUSF component versions and upgrade to 1.4.5
• Potential security incidents due to inadequate logging and monitoring

Technical summary

The free5GC AUSF component performs cryptographic authentication comparisons using insecure equality helpers, potentially allowing timing side-channel attacks. The vulnerability is fixed in version 1.4.5. Affected product context and defensive impact should be assessed. Official advisories and source-grounded technical framing should be reviewed without unsupported root-cause or exploit claims. Compensating controls and monitoring should be implemented while remediation is planned and verified. The issue allows attackers to potentially exploit timing discrepancies, although practical remote exploitation was not demonstrated.

Defensive priority

Defenders should prioritize verifying their AUSF component versions and upgrading to 1.4.5 if necessary. They should also assess their exposure to potential timing side-channel attacks and implement compensating controls to mitigate risks.

Recommended defensive actions

• Verify AUSF component version and upgrade to 1.4.5 if necessary
• Assess exposure to potential timing side-channel attacks
• Implement compensating controls to mitigate risks
• Monitor AUSF logs for potential security incidents
• Review relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. However, the corpus does not establish concrete exploitation or impact, requiring verification from official sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.