curl: Exposure of Data Element to Wrong Session
CVE-2026-107929 is a high-severity exposure of data element to wrong session vulnerability in curl, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected curl versions: 8.22.0 and earlier; 8.21.0 and earlier; 8.20.0 and earlier, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.67% chance of exploitation within 30 days, higher than 52% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of curl you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Curl | curl | 8.22.0 and earlier; 8.21.0 and earlier; 8.20.0 and earlier; 8.19.0 and earlier; 8.18.0 and earlier; 8.17.0 and earlier; 8.16.0 and earlier; 8.15.0 and earlier; and 11 more ranges | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
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
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Exposure of Data Element to Wrong Session
The product does not sufficiently enforce boundaries between the states of different sessions, causing data to be provided to, or used by, the wrong session.
How developers prevent this class of flaw
- Protect the application's sessions from information leakage. Make sure that a session's data is not used or visible by other sessions.
- Use a static analysis tool to scan the code for information leakage vulnerabilities (e.g. Singleton Member Field).
- In a multithreading environment, storing user data in Servlet member fields introduces a data access race condition. Do not use member fields to store information in the Servlet.
More Exposure of Data Element to Wrong Session vulnerabilities (CWE-488)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in curl
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.1 Critical severity
Recent Exposure of Data Element to Wrong Session vulnerabilities
- 9.1 Critical severity
- 7.3 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.4 High severity
- 10.0 Critical severity
Spotted an error? Tell us.