CVE-2026-86303

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

0.54% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 45.1% of scored records. A rank, not a probability.

NVD base score

6.9 (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:L/VA:L/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

Deferred. NVD last modified this record on 2026-09-08.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

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

2026-09-07 12:15Z1 MO AGO

Last updated

2026-09-08 12:57Z1 MO AGO

Reserved

2026-09-06

Assigning CNA

VulDB

Record state

PUBLISHED

Severity

Medium (CVSS 6.9)

CNA CVSS vector

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

Weaknesses

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass
• CWE-125Out-of-bounds ReadBase

Data version

5.2

Document digest

0bc8f1ec3cb9be2a1433b9cd526cb030bcf381179d76eba6417ce33087e7cee7

• vuldb.comVDB-399467 | 92181 markdown md.c lds out-of-boundshttps://vuldb.com/vuln/399467vdb-entrytechnical-description
• vuldb.comVDB-399467 | CTI Indicators (IOB, IOC, IOA)https://vuldb.com/vuln/399467/ctisignaturepermissions-required
• vuldb.comCVE-2026-86303 | CVE Analysis and Reporthttps://vuldb.com/cve/CVE-2026-86303third-party-advisory
• vuldb.comSubmit #907499 | github markdown commit 0d1eafb484f4766316a5391e162b4c96dc76513f Out-of-Bounds Readhttps://vuldb.com/submit/907499third-party-advisory
• github.comhttps://github.com/92181/markdown/issues/1issue-tracking
• github.comhttps://github.com/92181/markdown/pull/2issue-trackingpatch
• github.comhttps://github.com/92181/markdown/commit/c000d2f9cf390c315378d3717cf20911cf3e80a6patch
• github.comhttps://github.com/92181/markdown/product