When a remote, unauthenticated HTTP/1.1 client pipelined the start of a second request and then stopped reading, proxygen's coroutine-based HTTP session could free that pipelined stream while resetting the connection's streams on the resulting write timeout, then go on to use it....
Product
facebook proxygen vulnerabilities
17 published CVES affecting facebook proxygen, from public sources (CVE.org, NVD, CISA KEV, FIRST EPSS, OSV).
- Total
- 17
- Critical
- 3
- High
- 8
- Medium
- 2
- Low
- 0
- Unscored
- 4
- CISA KEV
- 1
Latest facebook proxygen CVEs
Newest publication first
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Unknown EPSS 0.19%
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Unknown EPSS 0.21%
In proxygen's HTTP/3 session, when a HEADERS block referenced QPACK dynamic table entries that had not yet been received, header decoding for that stream was paused, but the session continued to read the stream from the QUIC transport. The unread data bypassed the session's ingre...
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Unknown EPSS 0.18%
proxygen's QPACK decoder enforced its size limit on a string literal in an encoder-stream instruction only after the entire literal had been received. A remote, unauthenticated HTTP/3 peer could send an insert instruction on the QPACK encoder stream that declares an arbitrarily l...
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Unknown EPSS 0.18%
proxygen's HTTP/3 codec buffered an incomplete non-DATA frame, such as a control-stream frame, a frame of an unknown or reserved type, or a HEADERS frame, until its entire declared length had arrived, without limiting that length, and re-scanned all buffered data each time more b...
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HighCVSS 7.5 EPSS 0.26%
In proxygen from v2024.10.28.00 until v2026.09.28.00, WebTransportImpl::terminateSessionStreams (WebTransportImpl::destroy in releases before v2025.08.18.00) failed to unregister read callbacks for streams that were no longer open before destroying them. The transport could then...
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MediumCVSS 5.3 EPSS 0.25%
In proxygen from v2024.10.28.00 until v2026.09.28.00, the HTTPTransaction::onWebTransportUniStream and HTTPTransaction::onWebTransportBidiStream APIs could return stream handles that the stream handler had already freed. HQSession then installed those handles as transport read ca...
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CVE-2026-84895 proxygen: proxygen: Denial of Service via use-after-free during session closure
PublishedHighCVSS 7.3 EPSS 0.19%In proxygen from v2026.04.06.00 until v2026.09.28.00, QuicWtSession::closeSession accesses its member fields after calling the base QuicWtSessionBase::closeSession method. The base method notifies the session handler, which may release the last reference to the session and destro...
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HighCVSS 7.5 EPSS 0.57%
Proxygen lacked a generalized slow-consumer detection mechanism in its core HTTP session layer. A remote, unauthenticated attacker could exploit HTTP/2 flow-control by setting SETTINGS_INITIAL_WINDOW_SIZE to 0 or withholding WINDOW_UPDATE frames, causing the server to buffer comp...
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MediumCVSS 5.3 EPSS 0.31%
Sending an HTTP request/response body with greater than 2^31 bytes triggers an infinite loop in proxygen::coro::HTTPQuicCoroSession which blocks the backing event loop and unconditionally appends data to a std::vector per-loop iteration. This issue leads to unbounded memory growt...
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HighCVSS 7.5 EPSS 100.0% CISA KEV added 2023-10-10 Exploited in the wild Public exploit PoC
The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
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HighCVSS 7.5 EPSS 1.2%
A packet of death scenario is possible in mvfst via a specially crafted message during a QUIC session, which causes a crash via a failed assertion. Per QUIC specification, this particular message should be treated as a connection error. This issue affects mvfst versions prior to...
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CriticalCVSS 9.8 EPSS 1.1%
A use-after-free is possible due to an error in lifetime management in the request adaptor when a malicious client invokes request error handling in a specific sequence. This issue affects versions of proxygen prior to v2020.05.18.00.
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CriticalCVSS 9.8 EPSS 1.4%
In the course of decompressing HPACK inside the HTTP2 protocol, an unexpected sequence of header table resize operations can place the header table into a corrupted state, leading to a use-after-free condition and undefined behavior. This issue affects Proxygen from v0.29.0 until...
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CriticalCVSS 9.8 EPSS 2.1%
An out of bounds write is possible via a specially crafted packet in certain configurations of Proxygen due to improper handling of Base64 when parsing malformed binary content in Structured HTTP Headers. This issue affects versions of proxygen prior to v2019.07.22.00.
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HighCVSS 7.5 EPSS 1.4%
An issue in the Proxygen handling of HTTP2 parsing of headers/trailers can lead to a denial-of-service attack. This affects Proxygen prior to v2018.12.31.00.
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HighCVSS 7.5 EPSS 1.4%
A potential denial-of-service issue in the Proxygen handling of invalid HTTP2 priority settings (specifically a circular dependency). This affects Proxygen prior to v2018.12.31.00.
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HighCVSS 7.5 EPSS 0.83%
Proxygen fails to validate that a secondary auth manager is set before dereferencing it. That can cause a denial of service issue when parsing a Certificate/CertificateRequest HTTP2 Frame over a fizz (TLS 1.3) transport. This issue affects Proxygen releases starting from v2018.10...
Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.