Security readout for executives and security teams
Plain-English summary
Older HAProxy versions can mishandle unusual HTTP headers so security-relevant headers may disappear. If HAProxy uses or forwards those headers for access control, an unauthenticated remote attacker could bypass intended restrictions or disrupt service.
Executive priority
Treat this as urgent for HAProxy exposed to untrusted traffic. Patch promptly, starting with internet-facing proxies and environments where header-based access rules protect applications or admin paths.
Technical view
HAProxy before fixed releases accepted empty HTTP header field names in some parser paths. For HTTP/1.0 and HTTP/1.1 this could truncate the header list after parsing and processing, causing headers to disappear. HTTP/2 and HTTP/3 impact is described as limited because headers disappear before processing.
Likely exposure
Likely exposure is internet-facing or internal HAProxy deployments running before 2.7.3, 2.6.9, 2.5.12, 2.4.22, 2.2.29, or 2.0.31, especially where HTTP/1 traffic and header-based access-control decisions are used.
Exploitation context
The CVE is rated CVSS 9.1 and described as request smuggling with access-control bypass potential. The provided bundle does not show CISA KEV listing or cited evidence of active exploitation.
Researcher notes
Affected product metadata in the bundle is incomplete, but the CVE description and references identify HAProxy. Focus analysis on HTTP/1 parser behavior, CWE-444 request interpretation issues, and whether missing headers could change authorization, routing, or filtering outcomes.
Mitigation direction
- Upgrade HAProxy to a fixed upstream version for the deployed branch.
- Apply Debian or Fedora security updates where HAProxy is distribution-managed.
- Prioritize proxies enforcing access control or security routing from HTTP headers.
- Check HAProxy and distribution guidance before applying compensating controls.
- Avoid claiming mitigation by HTTP/2 or HTTP/3 alone without vendor confirmation.
Validation and detection
- Inventory all HAProxy instances and record exact versions.
- Confirm versions meet or exceed the fixed release for their branch.
- Identify frontends accepting HTTP/1.0 or HTTP/1.1 traffic.
- Review whether HAProxy rules depend on client-supplied headers.
- Verify distro package advisories show the security update installed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-444: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-25725 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H3.95.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.haproxy.org/CVE reference
- https://git.haproxy.org/?p=haproxy-2.7.git%3Ba=commit%3Bh=a0e561ad7f29ed50c473f5a9da664267b60d1112CVE reference
- [debian-lts-announce] 20230214 [SECURITY] [DLA 3318-1] haproxy security updateCVE reference · mailing-list
- DSA-5348CVE reference · vendor-advisory
- FEDORA-2023-7e04833463CVE reference · vendor-advisory
- FEDORA-2023-3e8a21cd5bCVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.