Unauthenticated service interruption via quadratic Range coalescing
Published Aug 25, 2026 · Updated Aug 25, 2026
Algorithmic complexity in libsoup3 on Red Hat Enterprise Linux 10 allows remote attackers to interrupt SoupServer services with Range headers. During range coalescing, soup_message_headers_get_ranges_internal() repeatedly calls g_array_remove_index(), turning many identical satisfiable ranges into O(N²) array moves. Reachability requires an unauthenticated request to a SoupServer handler that returns HTTP 200 with a non-empty body; the result is event-loop CPU blocking only, without data disclosure or corruption.
Summary
What happened
Algorithmic complexity in libsoup3 on Red Hat Enterprise Linux 10 allows remote attackers to interrupt SoupServer services with Range headers. During range coalescing, soup_message_headers_get_ranges_internal() repeatedly calls g_array_remove_index(), turning many identical satisfiable ranges into O(N²) array moves. Reachability requires an unauthenticated request to a SoupServer handler that returns HTTP 200 with a non-empty body; the result is event-loop CPU blocking only, without data disclosure or corruption.
The record
- CVE
- CVE-2026-77680
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-407, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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?
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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
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Weakness, pattern, technique
Public exploit references
- GNOME libsoup Range-header denial-of-service reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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