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Fencer Vulns
high 7.5

CVE-2021-30130 json

Improper Certificate Validation in phpseclib

published 2021-04-06 5 y ago modified 2026-09-10 1 mo ago also GHSA-vf4w-fg7r-5v94 , EUVD-2021-0879

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

phpseclib before 2.0.31 and 3.x before 3.0.7 mishandles RSA PKCS#1 v1.5 signature verification.

Patch / fix

  • packagist phpseclib/phpseclib 2.0.31, 3.0.7
  • phpseclib phpseclib 2.0.31, 3.0.7
  • phpseclib Debian 13, Debian 12 1.0.19-3
  • php-phpseclib Debian 14, Debian 13, Debian 12 2.0.30-2
  • php-phpseclib3 Debian 14, Debian 13, Debian 12 3.0.7-1

debian advisories DEBIAN-CVE-2021-30130

  • phpseclib Ubuntu Pro 20.04 LTS 1.0.18-2ubuntu0.1~esm1
  • php-phpseclib Ubuntu Pro 20.04 LTS 2.0.23-2ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2021-30130

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-30130 updated cvss 7.5

php-phpseclib: improper RSA PKCS#1 v1.5 signature verification

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
packagist phpseclib/phpseclib
>=3.0.0, <3.0.7
<2.0.31
3.0.7
2.0.31

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.