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VulnerabilityPublished Updated

CVE-2026-33745: yhirose cpp-httplib · Information Exposure

Affects yhirose cpp-httplibSource CVE Database V5

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Not known to be exploited · CVSS 7.4 High : upgrade to 0.39.0 soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
7.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.39.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 29 Oct 2026.

What to do

Upgrade cpp-httplib and yhirose/cpp-httplib to 0.39.0.

Affected software

ProductAffectedFixed in
yhirosecpp-httplibAffected
  • <0.39.0
Fixed in
  • 0.39.0
GitHubyhirose/cpp-httplibpkg:github/yhirose/cpp-httplibOther threatsAffected
  • <0.39.0
Fixed in
  • 0.39.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to cpp-httplib version 0.39.0 or later, where this vulnerability is fixed. No other mitigations are indicated by the vendor advisory. Patch status is confirmed by the version update information.

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.39.0, the cpp-httplib HTTP client forwards stored Basic Auth, Bearer Token, and Digest Auth credentials to arbitrary hosts when following cross-origin HTTP redirects (301/302/307/308). A malicious or compromised server can redirect the client to an attacker-controlled host, which then receives the plaintext credentials in the `Authorization` header. Version 0.39.0 fixes the issue.

References

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