Vulnerability in Haproxy

CVE-2023-25725

HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situations, aka "request smuggling." The HTTP header parsers in HAProxy may accept empty header field names, which could be used to truncate the list of HTTP headers and thus make some headers disappear after being parsed and processed for HTTP/1.0 and HTTP/1.1. For HTTP/2 and HTTP/3, the impact is limited because the headers disappear before being parsed and processed, as if they had not been sent by the client. The fixed versions are 2.7.3, 2.6.9, 2.5.12, 2.4.22, 2.2.29, and 2.0.31.

Vulnerability class: HTTP Request Smuggling

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.054 (92.5th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 92.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-25725: held from 0.055 to 0.054.

EPSS over last 30 days · oldest: 0.055 · newest: 0.054 · change: -0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-25725?
CVE-2023-25725 is a critical-severity vulnerability in Haproxy, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.1/10. Published 2023-02-14.
How severe is CVE-2023-25725?
Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2023-25725 known to be exploited?
7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.