CVE-2026-87823

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.43% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 37.2% of scored records. A rank, not a probability.

NVD base score

8.8 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-09-09.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-09 14:32Z1 MO AGO

Last updated

2026-09-09 16:13Z1 MO AGO

Reserved

2026-09-09

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-190Integer Overflow or WraparoundBase
• CWE-125Out-of-bounds ReadBase

Data version

5.2

Document digest

5362a8e302fbc8b95e9fa5a9aa7d7600936ce985cfce13846de8272ca26f83ba

• github.comGitHub Security Advisory (GHSA-jfr6-9xqw-2g2q)https://github.com/luben/zstd-jni/security/advisories/GHSA-jfr6-9xqw-2g2qvendor-advisory
• github.comFix commit: reject negative offset and size in the three direct-ByteBuffer nativeshttps://github.com/luben/zstd-jni/commit/d7a1c99322d5e1fc71932e722c0b5bb2fc525d3fpatch
• github.comUnchecked 32-bit bounds tests at v1.5.7-13https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/native/jni_zstd.ctechnical-description
• github.comNative declarations with no Java-side validation at v1.5.7-13https://github.com/luben/zstd-jni/blob/v1.5.7-13/src/main/java/com/github/luben/zstd/Zstd.javatechnical-description
• github.comzstd-jni v1.5.7-14 Release Noteshttps://github.com/luben/zstd-jni/releases/tag/v1.5.7-14release-notes
• github.comCommit that introduced the unchecked direct-ByteBuffer size natives (first released in 1.1.1)https://github.com/luben/zstd-jni/commit/46dcb2a54c8b8f2ce2cad7187a7513f509c533actechnical-descriptionpatch
• github.comhttps://github.com/luben/zstd-jniproduct
• www.vulncheck.comVulnCheck Advisory: zstd-jni 1.1.1 through 1.5.7-13 Out-of-Bounds Read via Direct ByteBuffer Frame-Size Methodshttps://www.vulncheck.com/advisories/zstd-jni-1.1.1-through-1.5.7-13-out-of-bounds-read-via-direct-bytebuffer-frame-size-methodsthird-party-advisory