CVE-2020-6620Public exploitNetwork attack vector

Application crash via unchecked font-buffer cursor

Published Jan 8, 2020 · Updated Aug 4, 2024

Heap buffer over-read in stb_truetype.h through 1.22 allows context-dependent attackers to crash applications via a crafted font. During CFF parsing, stbtt__buf_get8 reads past the heap-backed font buffer after malformed offsets drive its cursor beyond the allocation. Reachability requires an embedding application to process attacker-controlled fonts, and the public reproducer demonstrates an abort rather than code execution.

CVSS severity8.8
High
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer over-read in stb_truetype.h through 1.22 allows context-dependent attackers to crash applications via a crafted font. During CFF parsing, stbtt__buf_get8 reads past the heap-backed font buffer after malformed offsets drive its cursor beyond the allocation. Reachability requires an embedding application to process attacker-controlled fonts, and the public reproducer demonstrates an abort rather than code execution.

The record

CVE
CVE-2020-6620
Published
Jan 8, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

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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
T1203Exploitation for Client Execution

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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