Exploit discussion active in current signal (1 latest mentions)
Recommended action window: High priority (within 72h)
NVD 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.
Priority
MEDIUM
Exploitation
NONE
PoC
YES
Patch
AVAILABLE
Momentum
STABLE
| Date | Total | Labels |
|---|
| 2026-04-20 | 3 | Disclosure3 |
| 2026-04-27 | 1 | Disclosure1 |
| 2026-04-28 | 1 | General1 |
| 2026-05-13 | 1 | Disclosure1 |
| 2026-05-15 | 1 | Disclosure1 |
CVE-2026-5958: GNU sed: TOCTOU race in sed -i --follow-symlinks https://www.openwall.com/lists/oss-security/2026/05/13/1 Fixed in 4.10 (2026-04-21)
Post summary
A TOCTOU race condition in GNU sed's --follow-symlinks option was disclosed and fixed in version 4.10.
Most CVE writeups explain what happened. Few teach you how to think like an attacker. Just worked through CVE-2026-5958 step by step. Missed 1/5 questions - but learned way more. https://cveplayground.com #CyberSecurity #AppSec #CVE #BugBounty #InfoSec
Post summary
The user shares a learning experience on CVE-2026-5958 via cveplayground.com, indicating a walk-through but providing no exploit details, patches, or technical depth.
CVE-2026-5958: GNU sed 4.1e through 4.9 has a TOCTOU race condition. Run sed -i --follow-symlinks, and an attacker swapping a symlink between readlink() and open() causes sed to read from one file and write to another.
Post summary
The text discloses a TOCTOU race condition in GNU sed 4.1e‑4.9 and explains how an attacker can exploit it by swapping a symlink during sed’s "-i" operation with "--follow-symlinks".
CVE-2026-5958 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 sam… https://www.cve.org/CVERecord?id=CVE-2026-5958
Post summary
The excerpt provides a concise technical note on CVE-2026-5958, highlighting a race condition in sed, but contains no PoC, exploit, patch, or active exploitation information.
GNU Sed TOCTOU vulnerability (CVE-2026-5958) allows arbitrary file overwrite. Read more -> https://tinyurl.com/275m2696 #Security #Mageia https://t.co/11HKmdkmWO
Post summary
A new GNU Sed TOCTOU vulnerability (CVE-2026-5958) that permits arbitrary file overwrite has been disclosed, with a link for further details.
CVE-2026-5958 Race Condition Arbitrary File Overwrite in GNU sed with Symlink Following https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-5958
Post summary
The text announces the CVE‑2026‑5958 vulnerability, describing a race condition that allows arbitrary file overwrite via symlink following in GNU sed, without mentioning PoC, exploit code, or patches.
🚨*CVE* CVE-2026-5958 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 sam… https://www.cve.org/CVERecord?id=CVE-2026-5958 ----- Traducción: CVE-2026-5958 Cua… http://infoflow.cloud`
Post summary
The notice discloses CVE-2026-5958, detailing a non-atomic filesystem operation issue in sed when using -i and --follow-symlinks; no PoC, exploit, patch, or active exploitation is mentioned.