FTP wildcard write callback mixup
Affects libcurl 7.21.0 through 8.22.0 applications that enable CURLOPT_FTP_WILDCARD; the curl tool is not affected. curl rates it Low. 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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? →
- Specific setups only
- 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: yes
- Technical impact: partial
Summary
When an FTP wildcard `LIST` operation fails, libcurl omits the restoration path meant for successful listings, leaving the write callback set to the internal listing parser and the write callback data pointing directly to the easy handle. Subsequent reuse of this handle triggers an immediate crash, and cloning it via `curl_easy_duphandle()` copies this corrupted state into the duplicate. If the original handle is subsequently freed, executing a transfer on the cloned handle causes a heap use-after-free read against the dangling handle reference; alternatively, reusing the original or cloned handle while changing only `CURLOPT_WRITEDATA` (and omitting `CURLOPT_WRITEFUNCTION`) results in type confusion, forcing the internal parser to interpret incoming server response bytes into memory at the application-supplied write data pointer.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- 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; From 8.8.0 · through 8.8.0; From 8.7.1 · through 8.7.1; From 8.7.0 · through 8.7.0; From 8.6.0 · through 8.6.0; From 8.5.0 · through 8.5.0; From 8.4.0 · through 8.4.0; From 8.3.0 · through 8.3.0; From 8.2.1 · through 8.2.1; From 8.2.0 · through 8.2.0; From 8.1.2 · through 8.1.2; From 8.1.1 · through 8.1.1; From 8.1.0 · through 8.1.0; From 8.0.1 · through 8.0.1; From 8.0.0 · through 8.0.0; From 7.88.1 · through 7.88.1; From 7.88.0 · through 7.88.0; From 7.87.0 · through 7.87.0; From 7.86.0 · through 7.86.0; From 7.85.0 · through 7.85.0; From 7.84.0 · through 7.84.0; From 7.83.1 · through 7.83.1; From 7.83.0 · through 7.83.0; From 7.82.0 · through 7.82.0; From 7.81.0 · through 7.81.0; From 7.80.0 · through 7.80.0; From 7.79.1 · through 7.79.1; From 7.79.0 · through 7.79.0; From 7.78.0 · through 7.78.0; From 7.77.0 · through 7.77.0; From 7.76.1 · through 7.76.1; From 7.76.0 · through 7.76.0; From 7.75.0 · through 7.75.0; From 7.74.0 · through 7.74.0; From 7.73.0 · through 7.73.0; From 7.72.0 · through 7.72.0; From 7.71.1 · through 7.71.1; From 7.71.0 · through 7.71.0; From 7.70.0 · through 7.70.0; From 7.69.1 · through 7.69.1; From 7.69.0 · through 7.69.0; From 7.68.0 · through 7.68.0; From 7.67.0 · through 7.67.0; From 7.66.0 · through 7.66.0; From 7.65.3 · through 7.65.3; From 7.65.2 · through 7.65.2; From 7.65.1 · through 7.65.1; From 7.65.0 · through 7.65.0; From 7.64.1 · through 7.64.1; From 7.64.0 · through 7.64.0; From 7.63.0 · through 7.63.0; From 7.62.0 · through 7.62.0; From 7.61.1 · through 7.61.1; From 7.61.0 · through 7.61.0; From 7.60.0 · through 7.60.0; From 7.59.0 · through 7.59.0; From 7.58.0 · through 7.58.0; From 7.57.0 · through 7.57.0; From 7.56.1 · through 7.56.1; From 7.56.0 · through 7.56.0; From 7.55.1 · through 7.55.1; From 7.55.0 · through 7.55.0; From 7.54.1 · through 7.54.1; From 7.54.0 · through 7.54.0; From 7.53.1 · through 7.53.1; From 7.53.0 · through 7.53.0; From 7.52.1 · through 7.52.1; From 7.52.0 · through 7.52.0; From 7.51.0 · through 7.51.0; From 7.50.3 · through 7.50.3; From 7.50.2 · through 7.50.2; From 7.50.1 · through 7.50.1; From 7.50.0 · through 7.50.0; From 7.49.1 · through 7.49.1; From 7.49.0 · through 7.49.0; From 7.48.0 · through 7.48.0; From 7.47.1 · through 7.47.1; From 7.47.0 · through 7.47.0; From 7.46.0 · through 7.46.0; From 7.45.0 · through 7.45.0; From 7.44.0 · through 7.44.0; From 7.43.0 · through 7.43.0; From 7.42.1 · through 7.42.1; From 7.42.0 · through 7.42.0; From 7.41.0 · through 7.41.0; From 7.40.0 · through 7.40.0; From 7.39.0 · through 7.39.0; From 7.38.0 · through 7.38.0; From 7.37.1 · through 7.37.1; From 7.37.0 · through 7.37.0; From 7.36.0 · through 7.36.0; From 7.35.0 · through 7.35.0; From 7.34.0 · through 7.34.0; From 7.33.0 · through 7.33.0; From 7.32.0 · through 7.32.0; From 7.31.0 · through 7.31.0; From 7.30.0 · through 7.30.0; From 7.29.0 · through 7.29.0; From 7.28.1 · through 7.28.1; From 7.28.0 · through 7.28.0; From 7.27.0 · through 7.27.0; From 7.26.0 · through 7.26.0; From 7.25.0 · through 7.25.0; From 7.24.0 · through 7.24.0; From 7.23.1 · through 7.23.1; From 7.23.0 · through 7.23.0; From 7.22.0 · through 7.22.0; From 7.21.7 · through 7.21.7; From 7.21.6 · through 7.21.6; From 7.21.5 · through 7.21.5; From 7.21.4 · through 7.21.4; From 7.21.3 · through 7.21.3; From 7.21.2 · through 7.21.2; From 7.21.1 · through 7.21.1; From 7.21.0 · through 7.21.0
References 3
hackerone.com
Questions about CVE-2026-92388
What does this mean?
When an FTP wildcard LIST operation fails, libcurl skips a restoration step. Reusing an easy handle for or after that match can crash the application or read freed memory, and can make the parser write server response bytes to the application's write data pointer.Source: curl.se, curl.se
Am I affected, and how do I check?
Affected versions are curl 7.21.0 through 8.22.0, with some branch exceptions listed in the advisory. The flaw needs CURLOPT_FTP_WILDCARD enabled, and it affects libcurl applications, not the curl command line tool. Check the libcurl version your application links against and whether it sets CURLOPT_FTP_WILDCARD.Source: curl.se, curl.se
What should I do about it?
Upgrade libcurl to 8.23.0, the release the advisory names. The advisory also lists fixed versions 8.14.3, 8.16.2 and 8.20.2 for those branches.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