local interface connection reuse mixup
Only affects curl 8.9.0 through 8.22.0 when CURLOPT_INTERFACE or --interface uses an if!, host!, or ifhost! prefix. curl rates it Low against a CVSS score of 8.1. Fixed in 8.23.0.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- The rating the maker of the software gives it. Shown when it differs from the CVSS level.What do these mean? →
- Low (curl)
- Fix
- Fixed in 8.14.3, 8.16.2, 8.20.2, 8.23.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
When `CURLOPT_INTERFACE` (or the command line tool's `--interface` option) is set with one of the documented prefixes (`if!`, `host!`, `ifhost!`), that binding is not part of the connection reuse key, so a later transfer asking for a different source can silently reuse an existing connection and go out from the earlier transfer's source address
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- curl curl
From 8.22.0 · through 8.22.0; From 8.21.0 · through 8.21.0; From 8.20.0 · through 8.20.0; From 8.19.0 · through 8.19.0; From 8.18.0 · through 8.18.0; From 8.17.0 · through 8.17.0; From 8.16.0 · through 8.16.0; From 8.15.0 · through 8.15.0; From 8.14.1 · through 8.14.1; From 8.14.0 · through 8.14.0; From 8.13.0 · through 8.13.0; From 8.12.1 · through 8.12.1; From 8.12.0 · through 8.12.0; From 8.11.1 · through 8.11.1; From 8.11.0 · through 8.11.0; From 8.10.1 · through 8.10.1; From 8.10.0 · through 8.10.0; From 8.9.1 · through 8.9.1; From 8.9.0 · through 8.9.0
References 3
hackerone.com
Questions about CVE-2026-107929
What does this mean?
A later transfer can silently reuse an existing connection and send its traffic from the source address of the earlier transfer instead of the address it requested.Source: curl.se, curl.se
Am I affected, and how do I check?
Affected are curl and libcurl versions 8.9.0 through 8.22.0, including the point releases 8.9.1, 8.10.1, 8.11.1, 8.12.1, 8.14.1 and the other listed releases in that range. Run curl --version to see your version, then check whether your setup sets CURLOPT_INTERFACE or --interface with an if!, host! or ifhost! prefix.Source: curl.se, curl.se
What should I do about it?
Upgrade curl to 8.23.0, or to the backported releases 8.14.3, 8.16.2 or 8.20.2 if you stay on those branches. Until you upgrade, avoid CURLOPT_INTERFACE and --interface.Source: curl.se, curl.se
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data