CVE-2019-12900: bzip2 · Out-of-bounds Write
Source CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 7.9% chance of exploitation in 30 days – higher than 94% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jun 2019
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Debianbzip2pkg:deb/bzip2Other threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
- Immediate patching: Apply official patches or updates to the bzip2 library as soon as they become available. Monitor vendor advisories for embedded products that include bzip2 and update accordingly.
- Input validation and filtering: Implement strict validation on all incoming compressed data streams to detect and block suspicious or malformed bzip2 archives, especially those with an unusually high number of selectors.
- Use alternative compression methods: Where feasible, replace bzip2 with more secure or actively maintained compression libraries that do not have known critical vulnerabilities.
- Network segmentation and filtering: Restrict exposure of systems that decompress bzip2 data to untrusted networks. Use firewalls and intrusion detection systems to monitor and block anomalous decompression requests.
- Runtime protections: Employ memory protection mechanisms such as Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), and stack canaries to mitigate exploitation impact.
- Monitoring and incident response: Establish logging and alerting for decompression failures or crashes related to bzip2 usage to detect potential exploitation attempts early.
- Vendor coordination: Engage with software and hardware vendors to ensure timely patching of embedded bzip2 components in their products.
Description
BZ2_decompress in decompress.c in bzip2 through 1.0.6 has an out-of-bounds write when there are many selectors.
References
- lists.debian.org/debian-lts-announce/2019/06/msg00021.html (opens in a new tab)
- usn.ubuntu.com/4038-2/ (opens in a new tab)
- usn.ubuntu.com/4038-1/ (opens in a new tab)
- seclists.org/bugtraq/2019/Jul/22 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2019/07/msg00014.html (opens in a new tab)
- lists.opensuse.org/opensuse-security-announce/2019-07/msg00040.html (opens in a new tab)
- security.freebsd.org/advisories/FreeBSD-SA-19:18.bzip2.asc (opens in a new tab)
- seclists.org/bugtraq/2019/Aug/4 (opens in a new tab)
- lists.opensuse.org/opensuse-security-announce/2019-08/msg00050.html (opens in a new tab)
- usn.ubuntu.com/4146-1/ (opens in a new tab)
- usn.ubuntu.com/4146-2/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2019/10/msg00012.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2019/10/msg00018.html (opens in a new tab)
- lists.opensuse.org/opensuse-security-announce/2019-11/msg00078.html (opens in a new tab)
- lists.opensuse.org/opensuse-security-announce/2019-12/msg00000.html (opens in a new tab)
- lists.apache.org/thread.html/ra0adb9653c7de9539b93cc8434143b655f753b9f60580ff260becb2b%40%3Cusers.kafka.apache.org%3E (opens in a new tab)
- oracle.com/security-alerts/cpuoct2020.html (opens in a new tab)
- packetstormsecurity.com/files/153644/Slackware-Security-Advisory-bzip2-Updates.html (opens in a new tab)
- packetstormsecurity.com/files/153957/FreeBSD-Security-Advisory-FreeBSD-SA-19-18.bzip2.html (opens in a new tab)
- gitlab.com/federicomenaquintero/bzip2/commit/74de1e2e6ffc9d51ef9824db71a8ffee5962cdbc (opens in a new tab)
- support.f5.com/csp/article/K68713584?amp%3Butm_medium=RSS (opens in a new tab)
- lists.apache.org/thread.html/rda98305669476c4d90cc8527c4deda7e449019dd1fe9936b56671dd4%40%3Cuser.flink.apache.org%3E (opens in a new tab)
- lists.apache.org/thread.html/rce8cd8c30f60604b580ea01bebda8a671a25c9a1629f409fc24e7774%40%3Cuser.flink.apache.org%3E (opens in a new tab)