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CVE-2024-27354

phpseclib: guardrails needed on isPrime and randomPrime

7.5 HighFix available

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.60%Up 0.6 points since Mar 2, 2024
90%50%10%1%

What each source reports

CVE List Score used 7.5

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
CVE-2024-27354
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
EUVDEUVD-2024-0936 7.5

phpseclib: guardrails needed on isPrime and randomPrime

Record
EUVD-2024-0936
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-2528-jw5q-ww88 8.7

phpseclib: guardrails needed on isPrime and randomPrime

Impact

Anyone trying to generate a prime and testing the primality of a number.

Patches

https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575

Workarounds

Using the GMP extension would probably help, assuming that one has its own guardrails.

Resources

https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575 https://www.usenix.org/system/files/conference/usenixsecurity25/sec25cycle1-prepub-599-shi-bing.pdf

Record
GHSA-2528-jw5q-ww88
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
GitHub AdvisoriesGHSA-hg35-mp25-qf6h 8.7

Duplicate Advisory: phpseclib: guardrails needed on isPrime and randomPrime

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-2528-jw5q-ww88. This link is maintained to preserve external references.

Original Description

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
GHSA-hg35-mp25-qf6h
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
NVD 7.5

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
CVE-2024-27354
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
OSV 7.5

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
CVE-2024-27354
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 7 moreShow less
OSVDEBIAN-CVE-2024-27354 7.5

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
DEBIAN-CVE-2024-27354
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVGHSA-2528-jw5q-ww88 8.7

phpseclib: guardrails needed on isPrime and randomPrime

Impact

Anyone trying to generate a prime and testing the primality of a number.

Patches

https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575

Workarounds

Using the GMP extension would probably help, assuming that one has its own guardrails.

Resources

https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575 https://www.usenix.org/system/files/conference/usenixsecurity25/sec25cycle1-prepub-599-shi-bing.pdf

Record
GHSA-2528-jw5q-ww88
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
OSVGHSA-hg35-mp25-qf6h 8.7

Duplicate Advisory: phpseclib: guardrails needed on isPrime and randomPrime

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-2528-jw5q-ww88. This link is maintained to preserve external references.

Original Description

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
GHSA-hg35-mp25-qf6h
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
OSVUBUNTU-CVE-2024-27354 7.5

An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. An attacker can construct a malformed certificate containing an extremely large prime to cause a denial of service (CPU consumption for an isPrime primality check). NOTE: this issue was introduced when attempting to fix CVE-2023-27560.

Record
UBUNTU-CVE-2024-27354
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVCLSA-2026-1783386122 No score

TuxCare security update for phpseclib/phpseclib (1 CVE)

TuxCare rebuilt phpseclib/phpseclib to address 1 CVE. Fixed in 0.3.10-p3+tuxcare.

Record
CLSA-2026-1783386122
Updated
2026-11-02
OSVUSN-7404-1 No score

phpseclib vulnerabilities

It was discovered that phpseclib did not correctly handle RSA PKCS#1 v1.5 signature verification. An attacker could possibly use this issue to bypass authentication. This issue only affected Ubuntu 20.04 LTS. (CVE-2021-30130)

It was discovered that phpseclib did not correctly handle certain characters in certain TLS fields, which could lead to name confusion. An attacker could possibly use this issue to bypass authentication. (CVE-2023-52892)

It was discovered that phpseclib incorrectly limited the size of prime numbers generated by isPrime. An attacker could possibly use this issue to cause a denial of service. (CVE-2024-27354)

It was discovered that phpseclib did not correctly handle processing the ASN.1 object identifier of a certificate. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2024-27355)

Record
USN-7404-1
Updated
2026-11-02
OSVUSN-8769-1 No score

phpseclib vulnerability

It was discovered that phpseclib did not perform padding validation in constant time when using AES in CBC mode. A remote attacker could possibly use this issue to conduct a padding oracle timing attack and obtain sensitive information.

Record
USN-8769-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
phpseclib/phpseclib
Packagist
0.1.1 up to 1.0.23
1.0.23
phpseclib/phpseclib
Packagist
2.0.0 up to 2.0.47
2.0.47
phpseclib/phpseclib
Packagist
3.0.0 up to 3.0.36
3.0.36
phpseclib/phpseclib
TuxCare:Packagist
0.3.10 up to 0.3.10-p3+tuxcare, plus listed versions
0.3.10-p1+tuxcare0.3.10-p2+tuxcare
0.3.10-p3+tuxcare
php-phpseclib
Debian:12
before 2.0.42-1+deb12u2, plus listed versions
2.0.42-12.0.42-1+deb12u1
2.0.42-1+deb12u2
php-phpseclib
Debian:13
before 2.0.47-1
2.0.47-1
php-phpseclib
Debian:14
before 2.0.47-1
2.0.47-1
php-phpseclib3
Debian:12
before 3.0.19-1+deb12u3, plus listed versions
3.0.19-13.0.19-1+deb12u13.0.19-1+deb12u2
3.0.19-1+deb12u3
php-phpseclib3
Debian:13
before 3.0.36-1
3.0.36-1
php-phpseclib3
Debian:14
before 3.0.36-1
3.0.36-1
Show 32 moreShow less
Affected packages
PackageAffectedFixed
phpseclib
Debian:12
before 1.0.20-1+deb12u2, plus listed versions
1.0.20-11.0.20-1+deb12u1
1.0.20-1+deb12u2
phpseclib
Debian:13
before 1.0.23-1
1.0.23-1
phpseclib
Debian:10
From an advisory covering 2 CVEs
before 1.0.19-3~deb10u3, plus listed versions
1.0.14-11.0.15-11.0.16-11.0.16-21.0.17-1
Show 6 moreShow less
1.0.18-11.0.18-21.0.19-11.0.19-21.0.19-3~deb10u11.0.19-3~deb10u2
1.0.19-3~deb10u3
php-phpseclib
Debian:10
From an advisory covering 2 CVEs
before 2.0.30-2~deb10u3, plus listed versions
2.0.14-12.0.15-12.0.17-12.0.18-12.0.19-1
Show 16 moreShow less
2.0.20-12.0.21-12.0.21-22.0.21-32.0.22-12.0.23-12.0.23-22.0.25-12.0.26-12.0.27-12.0.28-12.0.29-12.0.29-22.0.30-12.0.30-2~deb10u12.0.30-2~deb10u2
2.0.30-2~deb10u3
phpseclib/phpseclib
Packagist
0.1.1 up to 1.0.23, plus listed versions
0.3.00.3.10.3.100.3.50.3.6
Show 26 moreShow less
0.3.70.3.80.3.91.0.01.0.11.0.101.0.111.0.121.0.131.0.141.0.151.0.161.0.171.0.181.0.191.0.21.0.201.0.211.0.221.0.31.0.41.0.51.0.61.0.71.0.81.0.9
1.0.23
phpseclib/phpseclib
Packagist
2.0.0 up to 2.0.47, plus listed versions
2.0.12.0.102.0.112.0.122.0.13
Show 41 moreShow less
2.0.142.0.152.0.162.0.172.0.182.0.192.0.22.0.202.0.212.0.222.0.232.0.242.0.252.0.262.0.272.0.282.0.292.0.32.0.302.0.312.0.322.0.332.0.342.0.352.0.362.0.372.0.382.0.392.0.42.0.402.0.412.0.422.0.432.0.442.0.452.0.462.0.52.0.62.0.72.0.82.0.9
2.0.47
phpseclib/phpseclib
Packagist
3.0.0 up to 3.0.36, plus listed versions
3.0.13.0.103.0.113.0.123.0.13
Show 21 moreShow less
3.0.143.0.153.0.163.0.173.0.183.0.193.0.23.0.203.0.213.0.223.0.233.0.33.0.333.0.343.0.353.0.43.0.53.0.63.0.73.0.83.0.9
3.0.36
php-phpseclib
Ubuntu:Pro:16.04:LTS
before 2.0.1-1ubuntu0.1~esm2, plus listed versions
2.0.1-12.0.1-1build1
2.0.1-1ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:16.04:LTS
before 1.0.1-3ubuntu0.1+esm1, plus listed versions
0.3.10-31.0.0-21.0.0-31.0.1-11.0.1-31.0.1-3ubuntu0.1
1.0.1-3ubuntu0.1+esm1
php-phpseclib
Ubuntu:Pro:18.04:LTS
before 2.0.9-1ubuntu0.1~esm2, plus listed versions
2.0.6-12.0.7-12.0.9-1
2.0.9-1ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:18.04:LTS
before 1.0.9-1ubuntu0.1~esm1, plus listed versions
1.0.7-11.0.8-11.0.9-1
1.0.9-1ubuntu0.1~esm1
php-phpseclib
Ubuntu:Pro:20.04:LTS
before 2.0.23-2ubuntu0.1~esm2, plus listed versions
2.0.21-22.0.23-2
2.0.23-2ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:20.04:LTS
before 1.0.18-2ubuntu0.1~esm1, plus listed versions
1.0.16-21.0.18-2
1.0.18-2ubuntu0.1~esm1
phpseclib
Ubuntu:22.04:LTS
before 1.0.20-1+deb12u3build0.22.04.1, plus listed versions
1.0.19-3ubuntu21.0.19-3ubuntu31.0.20-1
1.0.20-1+deb12u3build0.22.04.1
php-phpseclib
Ubuntu:Pro:22.04:LTS
before 2.0.36-1ubuntu0.1~esm2, plus listed versions
2.0.30-2ubuntu12.0.34-12.0.35-12.0.36-1
2.0.36-1ubuntu0.1~esm2
php-phpseclib3
Ubuntu:Pro:22.04:LTS
before 3.0.13-1ubuntu0.1~esm1, plus listed versions
3.0.9-13.0.10-13.0.12-23.0.13-1
3.0.13-1ubuntu0.1~esm1
phpseclib
Ubuntu:Pro:22.04:LTS
before 1.0.20-1ubuntu0.1~esm1, plus listed versions
1.0.19-3ubuntu21.0.19-3ubuntu31.0.20-1
1.0.20-1ubuntu0.1~esm1
php-phpseclib
Ubuntu:Pro:16.04:LTS
From an advisory covering 4 CVEs
before 2.0.1-1ubuntu0.1~esm2, plus listed versions
2.0.1-12.0.1-1build1
2.0.1-1ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:16.04:LTS
From an advisory covering 4 CVEs
before 1.0.1-3ubuntu0.1+esm1, plus listed versions
0.3.10-31.0.0-21.0.0-31.0.1-11.0.1-31.0.1-3ubuntu0.1
1.0.1-3ubuntu0.1+esm1
php-phpseclib
Ubuntu:Pro:18.04:LTS
From an advisory covering 4 CVEs
before 2.0.9-1ubuntu0.1~esm2, plus listed versions
2.0.6-12.0.7-12.0.9-1
2.0.9-1ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:18.04:LTS
From an advisory covering 4 CVEs
before 1.0.9-1ubuntu0.1~esm1, plus listed versions
1.0.7-11.0.8-11.0.9-1
1.0.9-1ubuntu0.1~esm1
php-phpseclib
Ubuntu:Pro:20.04:LTS
From an advisory covering 4 CVEs
before 2.0.23-2ubuntu0.1~esm2, plus listed versions
2.0.21-22.0.23-2
2.0.23-2ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:20.04:LTS
From an advisory covering 4 CVEs
before 1.0.18-2ubuntu0.1~esm1, plus listed versions
1.0.16-21.0.18-2
1.0.18-2ubuntu0.1~esm1
php-phpseclib
Ubuntu:Pro:22.04:LTS
From an advisory covering 4 CVEs
before 2.0.36-1ubuntu0.1~esm2, plus listed versions
2.0.30-2ubuntu12.0.34-12.0.35-12.0.36-1
2.0.36-1ubuntu0.1~esm2
php-phpseclib3
Ubuntu:Pro:22.04:LTS
From an advisory covering 4 CVEs
before 3.0.13-1ubuntu0.1~esm1, plus listed versions
3.0.9-13.0.10-13.0.12-23.0.13-1
3.0.13-1ubuntu0.1~esm1
phpseclib
Ubuntu:Pro:22.04:LTS
From an advisory covering 4 CVEs
before 1.0.20-1ubuntu0.1~esm1, plus listed versions
1.0.19-3ubuntu21.0.19-3ubuntu31.0.20-1
1.0.20-1ubuntu0.1~esm1
phpseclib
Ubuntu:Pro:16.04:LTS
From an advisory covering 5 CVEs
before 1.0.1-3ubuntu0.1+esm1, plus listed versions
0.3.10-31.0.0-21.0.0-31.0.1-11.0.1-31.0.1-3ubuntu0.1
1.0.1-3ubuntu0.1+esm1
phpseclib
Ubuntu:Pro:18.04:LTS
From an advisory covering 5 CVEs
before 1.0.9-1ubuntu0.1~esm2, plus listed versions
1.0.7-11.0.8-11.0.9-11.0.9-1ubuntu0.1~esm1
1.0.9-1ubuntu0.1~esm2
phpseclib
Ubuntu:Pro:20.04:LTS
From an advisory covering 5 CVEs
before 1.0.18-2ubuntu0.1~esm2, plus listed versions
1.0.16-21.0.18-21.0.18-2ubuntu0.1~esm1
1.0.18-2ubuntu0.1~esm2
phpseclib
Ubuntu:22.04:LTS
From an advisory covering 5 CVEs
before 1.0.20-1+deb12u3build0.22.04.1, plus listed versions
1.0.19-3ubuntu21.0.19-3ubuntu31.0.20-1
1.0.20-1+deb12u3build0.22.04.1
phpseclib
Ubuntu:Pro:24.04:LTS
From an advisory covering 5 CVEs
before 1.0.23-1ubuntu0.1~esm1, plus listed versions
1.0.21-21.0.22-11.0.23-1
1.0.23-1ubuntu0.1~esm1
phpseclib
Ubuntu:Pro:26.04:LTS
From an advisory covering 5 CVEs
before 1.0.24-1ubuntu0.1~esm1, plus listed versions
1.0.23-61.0.24-1
1.0.24-1ubuntu0.1~esm1

History

History
RecordedChangedSources
affected, facts
affected
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2024-27354 is a high vulnerability (CVSS 7.5) in Phpseclib, published March 1, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 48th percentile. Fixed in phpseclib/phpseclib 1.0.23.

References

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