How severe is CVE-2024-27354?

CVE-2024-27354 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-27354?

CVE-2024-27354 affects the following packages: phpseclib/phpseclib (Packagist), phpseclib/phpseclib (Packagist), phpseclib/phpseclib (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2024-27354?

Update phpseclib/phpseclib to 1.0.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27354 is resolved across your whole dependency graph.

How do I detect CVE-2024-27354 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpseclib/phpseclib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-27354 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2024-27354 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-27354 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-27354?

CVE-2024-27354 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 49th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-27354?

CVE-2024-27354 is classified as Uncontrolled Resource Consumption (CWE-400). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2024-27354 published, and has it been updated?

CVE-2024-27354 was published on March 1, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

HIGH severity

CVE-2024-27354 — phpseclib

HIGHFix: phpseclib/phpseclib@2870c8f

CVE-2024-27354 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in phpseclib/phpseclib. A fix is available for phpseclib/phpseclib — see the affected versions and patch details below.

phpseclib: guardrails needed on isPrime and randomPrime

Also known asGHSA-2528-jw5q-ww88

Published

Mar 1, 2024

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-27354.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk+0.00%

Lower risk than most CVEs49th percentile — riskier than 49% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐘phpseclib/phpseclib🐘phpseclib/phpseclib🐘phpseclib/phpseclib

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`phpseclib/phpseclib`	≥ 0.1.1&&< 1.0.23	1.0.23`composer require phpseclib/phpseclib:^1.0.23`
🐘Packagist	`phpseclib/phpseclib`	≥ 2.0.0&&< 2.0.47	2.0.47`composer require phpseclib/phpseclib:^2.0.47`
🐘Packagist	`phpseclib/phpseclib`	≥ 3.0.0&&< 3.0.36	3.0.36`composer require phpseclib/phpseclib:^3.0.36`

Affected Products

2 products · 4 configurations

debian linuxdebian

1 version

10.0

Application

phpseclibphpseclib

≥ 3.0.0 && < 3.0.36

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpseclib/phpseclib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update phpseclib/phpseclib to 1.0.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27354 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2024-27354 in your dependencies?

Find it across Packagist, including transitive dependencies.

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