Answer in brief
CVE-2026-85534 records a Unknown severity vulnerability in Libsoup: libsoup: http/2 client crash in on_data_source_read_callback when settings initial_window_size shrinks during deferred body read. The current sources do not mark it as known exploited. Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
Affected software not mapped in the current feed; confirm the named product and version against your inventory.
Published upstream
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 4, 2026
A flaw was found in libsoup. When a client sends an HTTP/2 request body from a non-pollable input stream, the library can buffer more data than the current flow-control window later allows. A malicious HTTP/2 server can shrink SETTINGS_INITIAL_WINDOW_SIZE while that buffered read is still in progress. The client then copies the full buffer into a smaller DATA callback without a runtime bounds check, which can abort the process or fail the HTTP/2 session.
Quoted source text, attributed separately from HOL analysis.