CVE-2026-88359

Process crash via cumulative stack allocation

Published Sep 24, 2026 · Updated Sep 24, 2026

Stack exhaustion in libfyaml 0.9.6 allows attackers to crash a consuming process by supplying a crafted YAML block scalar. fy_atom_iter_format() repeatedly calls alloca() while enlarging an internal buffer, so earlier allocations remain live until the function returns and cumulative stack use exceeds the process limit. Exploitation requires an application to parse an attacker-controlled, very large literal or folded block scalar, and the bounded consequence is a SIGSEGV service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.25%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Stack exhaustion in libfyaml 0.9.6 allows attackers to crash a consuming process by supplying a crafted YAML block scalar. fy_atom_iter_format() repeatedly calls alloca() while enlarging an internal buffer, so earlier allocations remain live until the function returns and cumulative stack use exceeds the process limit. Exploitation requires an application to parse an attacker-controlled, very large literal or folded block scalar, and the bounded consequence is a SIGSEGV service interruption.

The record

CVE
CVE-2026-88359
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started