Heap over-read via unbounded dynamic-table traversal
Published Aug 25, 2022 · Updated Aug 4, 2024
Heap-based buffer over-read in UPX 4.0.0 allows local users to read past allocated memory while processing a crafted executable. In PackLinuxElf32::invert_pt_dynamic, an unbounded loop walks entries until DT_NULL, letting acc_ua_get_be32 read a tag beyond the heap allocation. Exploitation requires UPX to process attacker-controlled input; the public report demonstrates an AddressSanitizer abort, while non-instrumented effects remain unestablished.
Summary
What happened
Heap-based buffer over-read in UPX 4.0.0 allows local users to read past allocated memory while processing a crafted executable. In PackLinuxElf32::invert_pt_dynamic, an unbounded loop walks entries until DT_NULL, letting acc_ua_get_be32 read a tag beyond the heap allocation. Exploitation requires UPX to process attacker-controlled input; the public report demonstrates an AddressSanitizer abort, while non-instrumented effects remain unestablished.
The record
- CVE
- CVE-2020-27799
- Published
- Aug 25, 2022
- Updated
- Aug 4, 2024
- Vendor
- The UPX Team
- Product
- UPX
- Classifications
- CWE-125, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2022CVE 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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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=upx 4.0.0-git-87b73e5cfdc1+
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.
Public exploit references
- Issue 391 proof-of-concept archiveproof of concept · demonstrated
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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