How severe is CVE-2026-19977?

CVE-2026-19977 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-19977 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-19977?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-19977 published?

CVE-2026-19977 was published on 2026-08-17 and last updated on 2026-08-20.

CVE-2026-19977

CVE-2026-19977 is a critical-severity vulnerability with a CVSS 3.x base score of 10.0. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 10.0
CVSS v4: 9.3
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Published: 2026-08-17
Last modified: 2026-08-20

Description

A vulnerability was detected in EFM ipTIME A3004T 14.19.0. The affected element is the function httpcon_check_session_url of the component Session Validation. Performing a manipulation results in improper authentication. Remote exploitation of the attack is possible. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Frequently asked questions

What is CVE-2026-19977?: A vulnerability was detected in EFM ipTIME A3004T 14.19.0. The affected element is the function httpcon_check_session_url of the component Session Validation. Performing a manipulation results in improper authentication. Remote exploitation of the attack is possible. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
How severe is CVE-2026-19977?: CVE-2026-19977 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-19977 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-19977?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-19977 published?: CVE-2026-19977 was published on 2026-08-17 and last updated on 2026-08-20.

References

Other CWE-287 (Improper Authentication) vulnerabilities

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CVE-2026-56191 — Critical (CVSS 10.0): Improper authentication in Microsoft Exchange Online allows an unauthorized attacker to perform tampering over a…

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