CVE-2026-46527: Cpp httplib · Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request
Affects cpp-httplibSource GCVE Database
Not known to be exploited · CVSS 7.5 High : upgrade to 0.44.0 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.44.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade yhirose/cpp-httplib to 0.44.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubyhirose/cpp-httplibpkg:github/yhirose/cpp-httplibOther threats | Affected
| Fixed in
|
Ubuntu Pro 22.04 LTScpp-httplibpkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTScpp-httplibpkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in– |
Ubuntu 25.10cpp-httplibpkg:deb/ubuntu/cpp-httplib?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 26.10cpp-httplibpkg:deb/ubuntu/cpp-httplib?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu Pro 26.04 LTScpp-httplibpkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps/resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade cpp-httplib to version 0.44.0 or later, where this vulnerability is fixed. No other mitigations are indicated or required.
Description
cpp-httplib versions prior to 0.44.0 contain a vulnerability when the server uses a non-empty trusted proxy list via Server::set_trusted_proxies(). An attacker can send an HTTP request with a malformed X-Forwarded-For header that leads to undefined behavior by causing the server to access an empty vector, resulting in abnormal process termination (denial of service). This issue is fixed in version 0.44.0.