How severe is CVE-2026-102270?

CVE-2026-102270 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-102270 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-102270?

CVE-2026-102270 affects Pyjwt Project Pyjwt. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-102270?

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

When was CVE-2026-102270 published?

CVE-2026-102270 was published on 2026-09-28 and last updated on 2026-10-06.

CVE-2026-102270

CVE-2026-102270 is a medium-severity vulnerability in Pyjwt Project Pyjwt with a CVSS 3.x base score of 4.4. 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-1333.

Key facts

Severity: Medium (CVSS 3.x base score 4.4)
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Pyjwt Project Pyjwt
Published: 2026-09-28
Last modified: 2026-10-06

Description

PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.

Frequently asked questions

What is CVE-2026-102270?: PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.
How severe is CVE-2026-102270?: CVE-2026-102270 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-102270 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-102270?: CVE-2026-102270 affects Pyjwt Project Pyjwt. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-102270?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-102270 published?: CVE-2026-102270 was published on 2026-09-28 and last updated on 2026-10-06.

References

Affected products (1)

cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*

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