How severe is CVE-2026-18929?

CVE-2026-18929 has a CVSS 4.0 base score of 6.9, rated medium severity.

Is CVE-2026-18929 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-18929?

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

When was CVE-2026-18929 published?

CVE-2026-18929 was published on 2026-08-18.

CVE-2026-18929

CVE-2026-18929 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.9. 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-409.

Key facts

Severity: Medium (CVSS 4.0 base score 6.9)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-409
Published: 2026-08-18
Last modified: 2026-08-18

Description

Carbone is vulnerable to Denial of Service due to lack of protection against zip bombs when processing .docx files. The library uses yazl for zip decompression without validating entry sizes, allowing an attacker to supply a malicious .docx file containing a zip bomb that decompresses to a significantly larger size, causing excessive memory consumption and crashing the application server. The issue was fixed in versions: 3.8.2, 4.26.3 and 5.4.4. The fix is available across all distribution types.

Frequently asked questions

What is CVE-2026-18929?: Carbone is vulnerable to Denial of Service due to lack of protection against zip bombs when processing .docx files. The library uses yazl for zip decompression without validating entry sizes, allowing an attacker to supply a malicious .docx file containing a zip bomb that decompresses to a significantly larger size, causing excessive memory consumption and crashing the application server. The issue was fixed in versions: 3.8.2, 4.26.3 and 5.4.4. The fix is available across all distribution types.
How severe is CVE-2026-18929?: CVE-2026-18929 has a CVSS 4.0 base score of 6.9, rated medium severity.
Is CVE-2026-18929 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-18929?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-18929 published?: CVE-2026-18929 was published on 2026-08-18.

References

Other CWE-409 vulnerabilities

CVE-2026-62963 — High (CVSS 8.7): Centrifugo is an open-source scalable real-time messaging server. Prior to 6.8.4, Centrifugo unidirectional WebSocket…
CVE-2026-55195 — High (CVSS 8.7): py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and…
CVE-2026-53430 — High (CVSS 8.7): Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-grpc grpc…
CVE-2026-44697 — High (CVSS 8.6): Klever-Go is the Go implementation of the Klever blockchain protocol. Prior to 1.7.17, a remote, unauthenticated…
CVE-2026-44981 — High (CVSS 8.2): CrowdSec offers crowdsourced protection against malicious IPs. From 1.7.0 until 1.7.8, the LAPI router used…
CVE-2026-43970 — High (CVSS 8.2): Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows…

Browse all CWE-409 vulnerabilities →