How severe is CVE-2026-55197?

CVE-2026-55197 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-55197 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-55197?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-55197 have an EU (EUVD) identifier?

Yes. CVE-2026-55197 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37778.

When was CVE-2026-55197 published?

CVE-2026-55197 was published on 2026-06-17.

CVE-2026-55197

CVE-2026-55197 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v4: 7.1
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-37778
Weakness: CWE-639
Published: 2026-06-17
Last modified: 2026-06-17

Description

Hermes WebUI before 0.51.443 contains a broken access control vulnerability in the /api/session endpoint that allows authenticated users to disclose cross-profile session transcripts. Attackers can bypass profile boundary checks by directly querying session IDs belonging to other profiles via GET /api/session?session_id=<foreign_id>&messages=1 to retrieve unauthorized conversation transcripts and metadata.

Frequently asked questions

What is CVE-2026-55197?: Hermes WebUI before 0.51.443 contains a broken access control vulnerability in the /api/session endpoint that allows authenticated users to disclose cross-profile session transcripts. Attackers can bypass profile boundary checks by directly querying session IDs belonging to other profiles via GET /api/session?session_id=<foreign_id>&messages=1 to retrieve unauthorized conversation transcripts and metadata.
How severe is CVE-2026-55197?: CVE-2026-55197 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-55197 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-55197?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-55197 have an EU (EUVD) identifier?: Yes. CVE-2026-55197 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37778.
When was CVE-2026-55197 published?: CVE-2026-55197 was published on 2026-06-17.

References

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