How severe is CVE-2023-49316?

CVE-2023-49316 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-49316?

CVE-2023-49316 affects the following packages: phpseclib/phpseclib (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2023-49316?

Update phpseclib/phpseclib to 3.0.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49316 is resolved across your whole dependency graph.

How do I detect CVE-2023-49316 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-2023-49316 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2023-49316 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-49316 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-2023-49316?

CVE-2023-49316 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 56th 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-2023-49316?

CVE-2023-49316 is classified as CWE-834 (CWE-834). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-49316 published, and has it been updated?

CVE-2023-49316 was published on November 27, 2023 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-2023-49316 — phpseclib

HIGHFix: phpseclib/phpseclib@964d781

CVE-2023-49316 is a high-severity (CVSS 7.5) CWE-834 vulnerability in phpseclib/phpseclib. A fix is available for phpseclib/phpseclib — see the affected versions and patch details below.

Phpseclib needs guardrails on large binaryfield integers

Also known asGHSA-2f25-pfq3-c7h8

Published

Nov 27, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs56th percentile — riskier than 56% 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

1 pkg affected

🐘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

Impact

Anyone loading untrusted ASN1 files (eg. X509 certificates, RSA PKCS8 private or public keys, etc)

Patches

https://github.com/phpseclib/phpseclib/commit/964d78101a70305df33f442f5490f0adb3b7e77f

Workarounds

No.

References

https://github.com/phpseclib/phpseclib/commit/964d78101a70305df33f442f5490f0adb3b7e77f https://www.usenix.org/system/files/usenixsecurity25-shi-bing.pdf

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`phpseclib/phpseclib`	≥ 3.0.0&&< 3.0.34	3.0.34`composer require phpseclib/phpseclib:^3.0.34`

Affected Products

1 product · 1 configurations

Application

phpseclibphpseclib

≥ 3.0.0 && < 3.0.34

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 3.0.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49316 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Anyone loading untrusted ASN1 files (eg. X509 certificates, RSA PKCS8 private or public keys, etc) ### Patches https://github.com/phpseclib/phpseclib/commit/964d78101a70305df33f442f5490f0adb3b7e77f ### Workarounds No. ### References https://github.com/phpseclib/phpseclib/commit/964d78101a70305df33f442f5490f0adb3b7e77f https://www.usenix.org/system/files/usenixsecurity25-shi-bing.pdf