CVE-2026-27654: NGINX ngx_http_dav_module vulnerability

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

25.9%

EPSS score, percentile 98 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

8.8 High

CVSS v4.0 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• from 1.29.0 to before 1.29.7
• from 0.5.13 to before 1.28.3
• from R36 to before R36 P3
• from R35 to before R35 P2
• R34
• R33

and 1 more in the table below

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Advisories and patches

• my.f5.com (Vendor advisory)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unknown.

Versions not listed are: unknown.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

NGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_dav_module module that might allow an attacker to trigger a buffer overflow to the NGINX worker process; this vulnerability may result in termination of the NGINX worker process or modification of source or destination file names outside the document root. This issue affects NGINX Open Source and NGINX Plus when the configurati…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-27654 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 24 Mar 2026.
• The CVE record carries a CVSS v4.0 base score of 8.8 (High), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 25.9% (percentile 98), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact partial.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

NGINX ngx_http_dav_module vulnerability

NGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_dav_module module that might allow an attacker to trigger a buffer overflow to the NGINX worker process; this vulnerability may result in termination of the NGINX worker process or modification of source or destination file names outside the document root. This issue affects NGINX Open Source and NGINX Plus when the configuration file uses DAV module MOVE or COPY methods, prefix location (nonregular expression location configuration), and alias directives. The integrity impact is constrained because the NGINX worker process user has low privileges and does not have access to the entire system. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline

Known exploited F5 vulnerabilities

• CVE-2026-94127: F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability (added 22 Sep 2026)
• CVE-2025-53521: F5 BIG-IP Stack-Based Buffer Overflow Vulnerability (added 27 Mar 2026)
• CVE-2023-46747: F5 BIG-IP Configuration Utility Authentication Bypass Vulnerability (added 31 Oct 2023)
• CVE-2023-46748: F5 BIG-IP Configuration Utility SQL Injection Vulnerability (added 31 Oct 2023)
• CVE-2022-1388: F5 BIG-IP Missing Authentication Vulnerability (added 10 May 2022)