CVE-2021-21826
A heap-based buffer overflow vulnerability exists in the XML Decompression DecodeTreeBlock functionality of AT&T Labs Xmill 0.7.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A heap-based buffer overflow vulnerability exists in the XML Decompression DecodeTreeBlock functionality of AT&T Labs Xmill 0.7. Within `DecodeTreeBlock` which is called during the decompression of an XMI file, a UINT32 is loaded from the file and used as trusted input as the length of a buffer. An attacker can provide a malicious file to trigger this vulnerability.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.14% probability · 66th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-120, CWE-787
- Affected
- att/xmill
- Source
- talos-cna@cisco.com
EPSS 1.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1291Exploit, Third Party Advisory
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1291Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.