CVE catalog
CVE-2020-24240
bison: CVE-2020-24240
- Severity
- Low
- Published
- Source
- [NVD] · [CVE record]
- EPSS
- 1.26% · Oct 25, 2026
GNU Bison before 3.7.1 has a use-after-free in _obstack_free in lib/obstack.c (called from gram_lex) when a '\0' byte is encountered. NOTE: there is a risk only if Bison is used with untrusted input, and the observed bug happens to cause unsafe behavior with a specific compiler/architecture. The bug report was intended to show that a crash may occur in Bison itself, not that a crash may occur in code that is generated by Bison.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | bison | sid | 2:3.8.2+dfsg-1 | fixed |
| Debian | bison | forky | 2:3.8.2+dfsg-1 | fixed |
| Debian | bison | trixie | 2:3.8.2+dfsg-1 | fixed |
| Debian | bison | bookworm | 2:3.8.2+dfsg-1 | fixed |
| Ubuntu | bison | 16.04 | 2:3.0.2.dfsg-2 | vulnerable |
| Ubuntu | bison | 16.04 | 2:3.0.4.dfsg-1 | vulnerable |
| Ubuntu | bison | 18.04 | 2:3.0.4.dfsg-1build1 | vulnerable |
| Ubuntu | bison | 20.04 | 2:3.4.1+dfsg-4 | vulnerable |
| Ubuntu | bison | 20.04 | 2:3.4.2+dfsg-1 | vulnerable |
| Ubuntu | bison | 20.04 | 2:3.5.1+dfsg-1 | vulnerable |
| Alpine | bison | 3.13 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.14 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.15 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.16 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.17 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.18 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.19 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.20 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.21 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.22 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.23 | 3.7.2-r0 | fixed |
| Alpine | bison | 3.24 | 3.7.2-r0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | bison | source | sid | 2:3.7.2+dfsg-1 | unimportant | Not reported | Not reported |
| Debian | bison | source | forky | 2:3.7.2+dfsg-1 | unimportant | Not reported | Not reported |
| Debian | bison | source | trixie | 2:3.7.2+dfsg-1 | unimportant | Not reported | Not reported |
| Debian | bison | source | bookworm | 2:3.7.2+dfsg-1 | unimportant | Not reported | Not reported |
| Alpine | bison | apk | 3.13 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.14 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.15 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.16 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.17 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.18 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.19 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.20 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.21 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.22 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.23 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
| Alpine | bison | apk | 3.24 | 3.7.2-r0 | Not reported | ALPINE-CVE-2020-24240 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [bison]Fixed
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b1· amd64 · bookwormFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · bookworm; dsa · bison · debian · 12
2:3.8.2+dfsg-1+b1· arm64 · bookwormFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · bookworm; dsa · bison · debian · 12
- [libbison-dev]Fixed
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b1· amd64 · bookwormFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · bookworm; dsa · bison · debian · 12
2:3.8.2+dfsg-1+b1· arm64 · bookwormFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · bookworm; dsa · bison · debian · 12
[Debian 13 (Trixie)]
- [bison]Fixed
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b2· amd64 · trixieFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · 13
2:3.8.2+dfsg-1+b2· arm64 · trixieFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · 13
- [libbison-dev]Fixed
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b2· amd64 · trixieFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · 13
2:3.8.2+dfsg-1+b2· arm64 · trixieFixed · Fixed:
2:3.7.2+dfsg-1dsa · bison · debian · 13
Observed: