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Public proof of conceptFix available

CVE-2021-20294

A public proof of concept exists; no exploitation attested.

  • Published2021-04-29
  • Fixed in2.35.2
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in binutils readelf 2.35 program. An attacker who is able to convince a victim using readelf to read a crafted file could trigger a stack buffer overflow, out-of-bounds write of arbitrary data supplied by the attacker. The highest impact of this flaw is to confidentiality, integrity, and availability.

Timeline

dates in UTC
  1. 2021-04-2916:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20294?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20294?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Gnu binutils
BranchAffectedFixed in
2.35≥ 2.35, < 2.35.22.35.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • binutilsSUSE:OpenStack Cloud Crowbar 9all versions · fixed in 2.37-9.44.1
  • binutilsSUSE:OpenStack Cloud Crowbar 8all versions · fixed in 2.37-9.44.1
  • binutilsSUSE:OpenStack Cloud 9all versions · fixed in 2.37-9.44.1
  • binutilsSUSE:OpenStack Cloud 8all versions · fixed in 2.37-9.44.1
  • binutilsSUSE:Linux Enterprise Software Development Kit 12 SP5all versions · fixed in 2.37-9.44.1and 2 other packages
  • binutilsSUSE:Linux Enterprise Server for SAP Applications 15 SP1all versions · fixed in 2.37-7.26.1
  • binutilsSUSE:Linux Enterprise Server for SAP Applications 15all versions · fixed in 2.37-6.23.1
  • binutilsSUSE:Linux Enterprise Server for SAP Applications 12 SP5all versions · fixed in 2.37-9.44.1

29 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-20294 Red Hat Product Security10 known affected

    binutils: stack buffer overflow WRITE may lead to a DoS via a crafted ELF

    binutils as a component of Red Hat Enterprise Linux 6 · binutils-devel as a component of Red Hat Enterprise Linux 6 · binutils as a component of Red Hat Enterprise Linux 7 · +7 more

Full record on NVD

Fix

  1. Update Gnu binutils to 2.35.2
  2. Workaround from the vendor Red Hat Product Security CVE-2021-20294 · 17 productsStack canaries, non-executable stack (NX), address space layout randomization (ASLR) are binary hardening protections enabled in Red Hat Enterprise Linux 7 and 8 that should greatly limit the impact of this flaw. An additional mitigation is to not use readelf to read files from untrusted sources. …
  3. No fix planned, says the vendor Red Hat Product Security CVE-2021-20294 · 5 productsOut of support scope
  4. No fix planned, says the vendor Red Hat Product Security CVE-2021-20294 · 5 productsWill not fix

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedtin-z/CVE-2021-20294-POC
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.8read 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-787known since 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score3.3 %2026-11-03
  • PoC-in-GitHubproof of concept1read 2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2021-04-29
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-20294?

A flaw was found in binutils readelf 2.35 program. An attacker who is able to convince a victim using readelf to read a crafted file could trigger a stack buffer overflow, out-of-bounds write of arbitrary data supplied by the attacker. The highest impact of this flaw is to confidentiality, integrity, and availability.

Is CVE-2021-20294 actively exploited?

Active exploitation of CVE-2021-20294 has not been confirmed. Its EPSS score was 3.3% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20294?

CVE-2021-20294 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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