How severe is CVE-2026-36721?

CVE-2026-36721 has a CVSS 3.x base score of 9.8, 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-2026-36721 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-36721?

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.

Does CVE-2026-36721 have an EU (EUVD) identifier?

Yes. CVE-2026-36721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35923.

When was CVE-2026-36721 published?

CVE-2026-36721 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-36721

CVE-2026-36721 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. 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-347.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35923
Weakness: CWE-347
Published: 2026-06-09
Last modified: 2026-06-17

Description

A lack of cryptographic signature verification in the validateAccessToken function of bookcars v8.3 allows attackers to bypass authentication via a forged JWT token.

Frequently asked questions

What is CVE-2026-36721?: A lack of cryptographic signature verification in the validateAccessToken function of bookcars v8.3 allows attackers to bypass authentication via a forged JWT token.
How severe is CVE-2026-36721?: CVE-2026-36721 has a CVSS 3.x base score of 9.8, 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-2026-36721 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-36721?: 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.
Does CVE-2026-36721 have an EU (EUVD) identifier?: Yes. CVE-2026-36721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35923.
When was CVE-2026-36721 published?: CVE-2026-36721 was published on 2026-06-09 and last updated on 2026-06-17.

References

https://github.com/CC-T-454455/Vulnerabilities/tree/master/bookcars/vulnerability-2

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