VulnerabilityPublished 22 Sep 2022Updated 27 May 2025

CVE-2022-35021: OTFCC · Classic Buffer Overflow

Source CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.9% chance of exploitation in 30 days – higher than 60% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Sep 2022
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

European organizations should implement the following specific mitigations: 1) Audit and inventory all software components and development tools to identify any usage of OTFCC or related font processing utilities. 2) Restrict processing of untrusted or unsolicited font files, especially those received via email or downloaded from external sources. 3) Employ sandboxing or containerization for font processing tools to limit the impact of potential exploitation. 4) Monitor for updates or patches from the OTFCC project or related maintainers and apply them promptly once available. 5) Implement application whitelisting and endpoint protection solutions that can detect anomalous behavior related to buffer overflows or crashes in font processing utilities. 6) Educate users about the risks of opening or processing untrusted font files, emphasizing cautious handling of email attachments and downloads. 7) Consider integrating static or dynamic analysis tools in the development pipeline to detect unsafe memory operations in custom font processing code.

Description

OTFCC commit 617837b was discovered to contain a global buffer overflow via /release-x64/otfccdump+0x718693.

Impact

For European organizations, the impact of CVE-2022-35021 depends largely on the usage of OTFCC tools within their software development or font processing pipelines. Organizations involved in digital publishing, graphic design, or software development that handle OpenType fonts might incorporate OTFCC or its components. Exploitation could lead to denial of service conditions, disrupting font processing workflows or automated build systems. While the vulnerability does not directly compromise confidentiality or integrity, availability impacts could affect operational continuity, especially in environments relying on automated font compilation or validation. Given the requirement for user interaction, exploitation might occur through crafted font files delivered via email or downloaded from untrusted sources, posing a risk to end-user systems processing such fonts. The absence of known exploits reduces immediate risk but does not eliminate the potential for future attacks, especially as font processing is a common vector for supply chain or document-based attacks.

Summary

CVE-2022-35021 is a medium-severity vulnerability identified as a global buffer overflow in the OTFCC project, specifically in the otfccdump component at the memory address offset +0x718693. OTFCC (OpenType Font C Compiler) is an open-source tool used for compiling and dumping OpenType font files. The vulnerability arises from improper bounds checking when processing font data, leading to a global buffer overflow condition. This type of vulnerability (CWE-120) can cause the program to crash or potentially allow an attacker to execute arbitrary code if exploited successfully. The CVSS 3.1 base score is 6.5, reflecting a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact is limited to availability (A:H), with no direct confidentiality or integrity impact reported. No known exploits are currently in the wild, and no vendor or product specifics beyond the OTFCC project are provided. The lack of patch links suggests that a fix may not yet be publicly available or that the vulnerability is relatively new and under assessment.

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #11
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.1 (opens in a new tab)
V14.1.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
MIME Conversion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 6 Jul 2025, 03:26 UTC

WeaknessesCWE-120

Technical details

References

Community reviews

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