Code execution via recursive nested tag parsing
Published Mar 23, 2021 · Updated Aug 4, 2024
Stack overflow in libass before 0.15.0 allows remote attackers to crash a consuming application or execute code via a crafted subtitle file. The parse_tags routine recursively processes nested transformation tags even though their parentheses cannot nest, allowing attacker-controlled tag depth to exhaust the call stack. Exploitation requires a consuming application to parse attacker-controlled ASS or SSA subtitles; the publicly demonstrated result is an application crash.
Summary
What happened
Stack overflow in libass before 0.15.0 allows remote attackers to crash a consuming application or execute code via a crafted subtitle file. The parse_tags routine recursively processes nested transformation tags even though their parentheses cannot nest, allowing attacker-controlled tag depth to exhaust the call stack. Exploitation requires a consuming application to parse attacker-controlled ASS or SSA subtitles; the publicly demonstrated result is an application crash.
The record
- CVE
- CVE-2020-24994
- Published
- Mar 23, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-770, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 23, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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