Client crash via signed GZIP extra length
Published Jul 12, 2023 · Updated Oct 23, 2024
Signed-to-unsigned conversion in Okio before 1.17.6 and 2.0.0 through 3.3.x allows remote attackers to crash clients via crafted GZIP data. GzipSource reads the little-endian two-byte FEXTRA XLEN field as a signed short, so values of 0x8000 or greater become negative before require() validates the length. A client must pass attacker-controlled GZIP data with a large extra-field length to GzipSource; the resulting exception can terminate an uncaught processing path and interrupt the consuming service.
Summary
What happened
Signed-to-unsigned conversion in Okio before 1.17.6 and 2.0.0 through 3.3.x allows remote attackers to crash clients via crafted GZIP data. GzipSource reads the little-endian two-byte FEXTRA XLEN field as a signed short, so values of 0x8000 or greater become negative before require() validates the length. A client must pass attacker-controlled GZIP data with a large extra-field length to GzipSource; the resulting exception can terminate an uncaught processing path and interrupt the consuming service.
The record
- CVE
- CVE-2023-3635
- Published
- Jul 12, 2023
- Updated
- Oct 23, 2024
- Vendor
- Block, Inc.
- Product
- Okio
- Classifications
- CWE-681, CWE-195, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 12, 2023CVE publishedPublication date reported by the CVE source.
- Oct 23, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.5.0 <1.0.0
- Affected versionversion=1.0.0 <1.17.6
- Affected versionversion=2.0.0 <3.0.0
- Affected versionversion=3.0.0 <3.4.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- GzipSource malformed-XLEN proof of conceptproof of concept · unverified
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
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