CVE-2021-33560
A public proof of concept exists; no exploitation attested.
- Published2021-06-08
- WeaknessCWE-203 · CWE-325
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « 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
Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.
Timeline
dates in UTC- 2021-06-0811:15CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-33560?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-33560?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.14 | = 1.14.0 | no fix published | NVD |
| 1.15 | = 1.15.0 | no fix published | NVD |
| 1.15 | = 1.15.1 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 33.x | = 33 | no fix published | NVD |
| 34.x | = 34 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.9 | ≥ 1.9.0, < 1.9.3 | 1.9.3 | NVD |
| 1.8 | < 1.8.8 | 1.8.8 | NVD |
5 more products in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
Advisories and patches
- dev.gnupg.orgRelease Notes · Vendor Advisory
- dev.gnupg.orgVendor Advisory
- dev.gnupg.orgRelease Notes · Vendor Advisory
- dev.gnupg.orgPatch · Vendor Advisory
- www.oracle.comPatch
- www.oracle.comPatch
Detection
read 2026-10-23 19:23 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 1 repository, unverifiedIBM/PGP-client-checker-CVE-2021-33560 PoC-in-GitHub
Sources
- CISA-ADPSSVC decisionnone2025-12-03
- OpenCVESSVC decisionnone—
- CISA-ADPCVSS 3.17.52025-12-03
- NVDCVSS 3.17.5read 2026-10-23
- NVDCVSS 2.05read 2026-10-23
- CISA-ADPweakness (CWE)CWE-3252025-12-03
- NVDweakness (CWE)CWE-203read 2026-10-23
- FIRST EPSSEPSS score2.4 %2026-10-22
- PoC-in-GitHubproof of concept1read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2021-06-08
- Last Modified
- 2026-10-14
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-33560?
Is CVE-2021-33560 actively exploited?
What is the CVSS score for CVE-2021-33560?
Hear about the next vulnerability in your software
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
No credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.