CVE-2026-5958
Description
When sed is invoked with both -i (in-place edit) and --follow-symlinks, the function open_next_file() performs two separate, non-atomic filesystem operations on the same path: 1. resolves symlink to its target and stores the resolved path for determining when output is written, 2. opens the original symlink path (not the resolved one) to read the file. Between these two calls there is a race window. If an attacker atomically replaces the symlink with a different target during that window, sed will: read content from the new (attacker-chosen) symlink target and write the processed result to the path recorded in step 1. This can lead to arbitrary file overwrite with attacker-controlled content in the context of the sed process. This issue was fixed in version 4.10.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
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OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 4.9-1+deb12u1 |
| debian | bullseye | affected | |
| debian | forky | fixed | 4.9-3 |
| debian | sid | fixed | 4.9-3 |
| debian | trixie | fixed | 4.9-2+deb13u1 |
References
CWEs
CWE-367
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.