CVE-2020-29573: gnu glibc Out-of-bounds Write
Vulnerability summary
CVE-2020-29573 is a high (CVSS 7.5) Out-of-bounds Write vulnerability in gnu glibc. EPSS estimates a 2.72% chance of exploitation in the next 30 days, higher than 86% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 3% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 9 · Related 6Timeline
- 05-12-2020PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
Description
sysdeps/i386/ldbl2mpn.c in the GNU C Library (aka glibc or libc6) before 2.23 on x86 targets has a stack-based buffer overflow if the input to any of the printf family of functions is an 80-bit long double with a non-canonical bit pattern, as seen when passing a \x00\x04\x00\x00\x00\x00\x00\x00\x00\x04 value to sprintf. NOTE: the issue does not affect glibc by default in 2016 or later (i.e., 2.23 or later) because of commits made in 2015 for inlining of C99 math functions through use of GCC built-ins. In other words, the reference to 2.23 is intentional despite the mention of "Fixed for glibc 2.33" in the 26649 reference.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · Red hatEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
2.72%
Chance of exploitation in the next 30 days
Percentile
86%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.72% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat10 products
- enterprise_linuxEOL7.0
- glibc< 0:2.17-196.el7_4.4
- glibc-common< 0:2.17-196.el7_4.4
- glibc-debuginfo< 0:2.17-196.el7_4.4
- glibc-debuginfo-common< 0:2.17-196.el7_4.4
Netapp2 products
Debian1 product
- glibc< 2.23-1
Gnu1 product
- glibc< 2.23
Ubuntu1 product
- eglibcAll versions (No fix recorded)
5 vendors · 15 products
References
14 links- sourceware.org/bugzilla/show_bug.cgi?id=26649X Refsource MISCIssue TrackingPatchThird Party Advisory
- sourceware.org/pipermail/libc-alpha/2020-September/117779.htmlX Refsource MISCARTICLEREPORTPatchThird Party Advisory
