How severe is CVE-2026-31988?

No CVSS score has been assigned to CVE-2026-31988 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-31988?

CVE-2026-31988 affects the following packages: yauzl (npm). Ecosystems affected: npm.

How do I fix CVE-2026-31988?

Update yauzl to 3.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31988 is resolved across your whole dependency graph.

How do I detect CVE-2026-31988 in my npm dependencies?

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

How do I mitigate CVE-2026-31988 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.

How does O3 Security protect against CVE-2026-31988?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-31988 can be triaged on real exposure rather than presence alone.

Is CVE-2026-31988 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-31988 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-2026-31988?

CVE-2026-31988 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-2026-31988?

CVE-2026-31988 is classified as CWE-193 (CWE-193). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-31988 published, and has it been updated?

CVE-2026-31988 was published on March 11, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-31988: yauzl DoS

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-31988.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

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

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

yauzlnpm

36.6Mdownloads / week

Description

yauzl (aka Yet Another Unzip Library) version 3.2.0 for Node.js contains an off-by-one error in the NTFS extended timestamp extra field parser within the getLastModDate() function. The while loop condition checks cursor < data.length + 4 instead of cursor + 4 <= data.length, allowing readUInt16LE() to read past the buffer boundary. A remote attacker can cause a denial of service (process crash via ERR_OUT_OF_RANGE exception) by sending a crafted zip file with a malformed NTFS extra field. This affects any Node.js application that processes zip file uploads and calls entry.getLastModDate() on parsed entries. Fixed in version 3.2.1.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`yauzl`	≥ 3.2.0&&< 3.2.1	3.2.1`npm install yauzl@3.2.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yauzl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yauzl to 3.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31988 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-31988 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-31988. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Moderate: This flaw in yauzl can lead to a denial of service in Node.js applications that process zip file uploads and specifically call `entry.getLastModDate()` on parsed entries. Red Hat products that utilize the affected `yauzl` library in this manner are susceptible to a process crash when handling a specially…

Product	Fixed in	Advisory
Red Hat Developer Hub 1.10	`rhdh/rhdh-hub-rhel9:1780930740`	RHSA-2026:24841

Frequently Asked Questions

yauzl (aka Yet Another Unzip Library) version 3.2.0 for Node.js contains an off-by-one error in the NTFS extended timestamp extra field parser within the getLastModDate() function. The while loop condition checks cursor < data.length + 4 instead of cursor + 4 <= data.length, allowing readUInt16LE() to read past the buffer boundary. A remote attacker can cause a denial of service (process crash via ERR_OUT_OF_RANGE exception) by sending a crafted zip file with a malformed NTFS extra field. This affects any Node.js application that processes zip file uploads and calls entry.getLastModDate() on p

O3 Security · Impact-Aware SCA

Is CVE-2026-31988 in your dependencies?

O3 Security finds CVE-2026-31988 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works

CVE-2026-31988 — yauzl