Distribution advisory
This page covers CVE-2023-4639 as tracked by Debian, for the package undertow. The fix is available in version 2.3.18-1; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Attack vector: Network — reachable from anywhere that can route to the service.
- Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: High — total loss, or loss the attacker controls.
- Integrity impact: High — total loss, or loss the attacker controls.
- Availability impact: None.
Weakness class
DEBIAN-CVE-2023-4639 is classified as CWE-444: HTTP Request Smuggling. A proxy and a server disagree on where one request ends, letting an attacker slip a second request past the front end.
Affected software
DEBIAN-CVE-2023-4639 is recorded against 1 package.
- undertow (fixed in 2.3.18-1)
Timeline and source
Published on 17 November 2024 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
security-tracker.debian.org (Advisory)
Other advisories for this package
undertow has other advisories on record. If you are patching this one, these are worth checking on the same host:
Same weakness in other software
These advisories are the same class of weakness (CWE-444: HTTP Request Smuggling) in other software:
