Security Resilience

CVE-2023-3635

Squareup Okio 0.5.0 – 1.17.6

Public PoC
Published
12 July 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.013 69th percentile
Risk Priority 48 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-3635 is a medium-severity Signed to Unsigned Conversion Error (CWE-195) vulnerability in Squareup Okio. Its CVSS base score is 5.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 31% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability Data

GzipSource does not handle an exception that might be raised when parsing a malformed gzip buffer. This may lead to denial of service of the Okio client when handling a crafted GZIP archive, by using the GzipSource class.

CWE(s)
CWE-195CWE-681

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
attack.mitre.org →
T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
attack.mitre.org →
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-45799Same vendor: Squareup
CVE-2023-28063Shared CWE-195, CWE-681
CVE-2023-5184Shared CWE-195, CWE-681
CVE-2024-7747Shared CWE-681
CVE-2024-32481Shared CWE-681
CVE-2026-47508Shared CWE-681
CVE-2025-65495Shared CWE-195
CVE-2026-24192Shared CWE-681
CVE-2026-83872Shared CWE-681
CVE-2026-4602Shared CWE-681

Affected Assets

squareup
okio
0.5.0 — 1.17.6 · 2.0.0 — 3.4.0

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices (static analysis, code review, safe-integer standards) directly prevent signed-to-unsigned conversion errors.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.19 Installation of software on operational systems partial match
removes
A.8.25 Secure development life cycle partial match
blocks

Secure development life cycle mandates practices that can catch signed-to-unsigned conversion errors during design and coding.

A.8.26 Application security requirements partial match
blocks

A.8.26 only requires that security requirements (including resilience against attacks such as buffer overflows or SQL injection) be identified and specified during development or acquisition; it does not itself enforce, implement, or prevent the signed-to-unsigned conversion error from arising or being exploitable.

A.8.27 Secure system architecture and engineering principles partial match
blocks

A.8.27 mandates establishing and applying security engineering principles (e.g. least privilege, security by design, hardening) and design reviews during the SDLC; it does not stop a signed-to-unsigned conversion error from being exploitable if the flawed code is written and deployed.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit unsafe signed-to-unsigned casts and require defensive checks.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing in development can detect conversion-related defects before release.

References