How severe is CVE-2025-6998?

CVE-2025-6998 has a CVSS 4.0 base score of 8.7, rated high severity.

Is CVE-2025-6998 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-6998?

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

Does CVE-2025-6998 have an EU (EUVD) identifier?

Yes. CVE-2025-6998 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22540.

When was CVE-2025-6998 published?

CVE-2025-6998 was published on 2025-07-24 and last updated on 2026-06-17.

CVE-2025-6998

CVE-2025-6998 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. 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: High (CVSS 4.0 base score 8.7)
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-22540
Weakness: CWE-1333
Published: 2025-07-24
Last modified: 2026-06-17

Description

ReDoS in strip_whitespaces() function in cps/string_helper.py in Calibre Web and Autocaliweb allows unauthenticated remote attackers to cause denial of service via specially crafted username parameter that triggers catastrophic backtracking during login. This issue affects Calibre Web: 0.6.24 (Nicolette); Autocaliweb: from 0.7.0 before 0.7.1.

Frequently asked questions

What is CVE-2025-6998?: ReDoS in strip_whitespaces() function in cps/string_helper.py in Calibre Web and Autocaliweb allows unauthenticated remote attackers to cause denial of service via specially crafted username parameter that triggers catastrophic backtracking during login. This issue affects Calibre Web: 0.6.24 (Nicolette); Autocaliweb: from 0.7.0 before 0.7.1.
How severe is CVE-2025-6998?: CVE-2025-6998 has a CVSS 4.0 base score of 8.7, rated high severity.
Is CVE-2025-6998 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-6998?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-6998 have an EU (EUVD) identifier?: Yes. CVE-2025-6998 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22540.
When was CVE-2025-6998 published?: CVE-2025-6998 was published on 2025-07-24 and last updated on 2026-06-17.

References

Other CWE-1333 vulnerabilities

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CVE-2023-29487 — Critical (CVSS 9.1): An issue was discovered in Heimdal Thor agent versions 3.4.2 and before on Windows and 2.6.9 and before on macOS,…
CVE-2026-47138 — High (CVSS 8.7): Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to…
CVE-2020-26310 — High (CVSS 8.7): Validate.js provides a declarative way of validating javascript objects. All versions as of 30 November 2020 contain…

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