CVE-2026-5314Public exploitNetwork attack vector

Application crash via unchecked cmap table offset

Published Apr 1, 2026 · Updated Apr 1, 2026

Out-of-bounds read in stb through 1.26 allows remote attackers to interrupt applications that process a crafted TrueType or OpenType font. During stbtt_InitFont_internal, ttUSHORT reads two bytes through a malformed cmap table-directory offset without checking the font buffer boundary. Exploitation requires an application to pass attacker-controlled font data to stbtt_InitFont and can crash the consuming process.

CVSS severity4.3
Medium
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in stb through 1.26 allows remote attackers to interrupt applications that process a crafted TrueType or OpenType font. During stbtt_InitFont_internal, ttUSHORT reads two bytes through a malformed cmap table-directory offset without checking the font buffer boundary. Exploitation requires an application to pass attacker-controlled font data to stbtt_InitFont and can crash the consuming process.

The record

CVE
CVE-2026-5314
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Sean Barrett
Product
stb
Classifications
CWE-125, CWE-119, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0
  2. Affected versionversion=1.1
  3. Affected versionversion=1.10
  4. Affected versionversion=1.11
  5. Affected versionversion=1.12
  6. Affected versionversion=1.13
  7. Affected versionversion=1.14
  8. Affected versionversion=1.15
  9. Affected versionversion=1.16
  10. Affected versionversion=1.17
  11. Affected versionversion=1.18
  12. Affected versionversion=1.19
  13. Affected versionversion=1.2
  14. Affected versionversion=1.20
  15. Affected versionversion=1.21
  16. Affected versionversion=1.22
  17. Affected versionversion=1.23
  18. Affected versionversion=1.24
  19. Affected versionversion=1.25
  20. Affected versionversion=1.26
  21. Affected versionversion=1.3
  22. Affected versionversion=1.4
  23. Affected versionversion=1.5
  24. Affected versionversion=1.6
  25. Affected versionversion=1.7
  26. Affected versionversion=1.8
  27. Affected versionversion=1.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sean Barrett · stbversion=1.0; version=1.1; version=1.10; version=1.11; version=1.12; version=1.13; version=1.14; version=1.15; version=1.16; version=1.17; version=1.18; version=1.19; version=1.2; version=1.20; version=1.21; version=1.22; version=1.23; version=1.24; version=1.25; version=1.26; version=1.3; version=1.4; version=1.5; version=1.6; version=1.7; version=1.8; version=1.9

Published CVSS scores

4.3VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
5.0VulDBAV:N/AC:L/Au:N/C:N/I:N/A:P
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1204.002Malicious File

Public exploit references

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

Technologies

Your stack

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Your stack

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