Heap corruption via undersized Montgomery buffer
Published Sep 23, 2026 · Updated Sep 23, 2026
Heap buffer overflow in BusyBox TLS allows remote attackers to corrupt heap memory via a crafted ClientKeyExchange message. The Montgomery-reduction path allocates a temporary buffer in bytes where the arithmetic code expects a count of multi-byte digits, so processing the attacker-controlled key exchange writes beyond the allocation. The TLS server must expose BusyBox's built-in TLS implementation before authentication; no consequence beyond heap memory corruption has been published.
Summary
What happened
Heap buffer overflow in BusyBox TLS allows remote attackers to corrupt heap memory via a crafted ClientKeyExchange message. The Montgomery-reduction path allocates a temporary buffer in bytes where the arithmetic code expects a count of multi-byte digits, so processing the attacker-controlled key exchange writes beyond the allocation. The TLS server must expose BusyBox's built-in TLS implementation before authentication; no consequence beyond heap memory corruption has been published.
The record
- CVE
- CVE-2026-88830
- Published
- Sep 23, 2026
- Updated
- Sep 23, 2026
- Vendor
- Commonhaus Foundation
- Product
- Red Hat Hardened Images
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 23, 2026CVE publishedPublication date reported by the CVE source.
- Sep 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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