CVE-2026-42934
CVE-2026-42934 is a medium-severity vulnerability in F5 Dos with a CVSS 3.x base score of 4.8. 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-125.
Key facts
- Severity: Medium (CVSS 3.x base score 4.8)
- CVSS v4: 6.3
- EPSS exploit prediction: 1% (49th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-30008
- Weakness: CWE-125
- Affected product: F5 Dos
- Published:
- Last modified:
Description
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When charset, source_charset, and charset_map and proxy_pass with disabled buffering ("off") directives are configured, unauthenticated attackers can send requests that with conditions beyond the attackers' control to cause a heap buffer over-read in the NGINX worker process, leading to limited disclosure of memory or a restart. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Frequently asked questions
- What is CVE-2026-42934?
- NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When charset, source_charset, and charset_map and proxy_pass with disabled buffering ("off") directives are configured, unauthenticated attackers can send requests that with conditions beyond the attackers' control to cause a heap buffer over-read in the NGINX worker process, leading to limited disclosure of memory or a restart. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
- How severe is CVE-2026-42934?
- CVE-2026-42934 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.
- Is CVE-2026-42934 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-42934?
- CVE-2026-42934 primarily affects F5 Dos. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-42934?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-42934 have an EU (EUVD) identifier?
- Yes. CVE-2026-42934 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30008.
- When was CVE-2026-42934 published?
- CVE-2026-42934 was published on 2026-05-13 and last updated on 2026-06-18.
References
Affected products (8)
- cpe:2.3:a:f5:dos:*:*:*:*:*:nginx:*:*
- cpe:2.3:a:f5:dos:4.8.0:*:*:*:*:nginx:*:*
- cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:*
- cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:*
- cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:*
- cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:*
- cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*
- cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:*
More vulnerabilities in F5 Dos
- CVE-2026-42055 — High (CVSS 8.1): NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and…
- CVE-2026-42945 — High (CVSS 8.1): NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists…
- CVE-2026-42946 — Medium (CVSS 6.5): A vulnerability exists in the ngx_http_scgi_module and ngx_http_uwsgi_module modules that may result in excessive…
- CVE-2026-40460 — Medium (CVSS 6.5): When NGINX Plus or NGINX Open Source are configured to use the HTTP/3 QUIC module, an attacker may be able to spoof…
- CVE-2026-48142 — Medium (CVSS 4.8): NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When content is served or…
- CVE-2026-40701 — Medium (CVSS 4.8): NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssl_module module when the…
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