Red Hat Security Advisory: libsoup3 security update

Fixed packages 5

Vulnerabilities 9

• High 8.6
  CVE-2026-102556

  Libsoup: libsoup: heap buffer overflow from websocket pong signal type confusion

  A flaw was found in libsoup. When handling an incoming WebSocket Pong frame, SoupWebsocketConnection emitted the ::pong signal with a GByteArray pointer even though the signal is declared to pass a GBytes. Applications connecting a handler that follows the do…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 8.6
  CVE-2026-102557

  Libsoup: libsoup: heap buffer overflow during websocket message reassembly

  A flaw was found in libsoup. When reassembling fragmented WebSocket messages into a GByteArray, libsoup did not adequately cap total message size against the limits of the underlying buffer type. A remote peer could send fragments that caused size truncation …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 8.6
  CVE-2026-102558

  Libsoup: libsoup: heap buffer overflow during websocket receive-buffer growth

  A flaw was found in libsoup. When max-incoming-payload-size is unlimited (0), SoupWebsocketConnection could grow its incoming GByteArray based on an attacker-controlled frame length until the length wrapped, causing a heap buffer overflow while reading frame …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 8.6
  CVE-2026-102559

  Libsoup: libsoup: heap buffer overflow during websocket client-frame masking

  A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer o…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 6 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 8.6
  CVE-2026-102560

  Libsoup: libsoup: heap buffer overflow during outgoing permessage-deflate buffer growth

  A flaw was found in libsoup. When the permessage-deflate WebSocket extension compresses a very large outgoing message, truncated size calculations used for GByteArray growth could wrap, causing zlib to write past the allocated buffer and resulting in a heap b…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 7 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 8.2
  CVE-2026-102555

  Libsoup: libsoup: heap buffer overflow via uninitialized length in data-uri base64 decoding

  A flaw was found in libsoup. The soup_uri_decode_data_uri() function incorrectly treated base64 data-URI payloads as NUL-terminated strings when calling g_base64_decode_inplace(). If the percent-decoded payload contained embedded NUL bytes, the decoded length…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 7 Linux Debian Ubuntu Azure Linux
  Sep 29, 2026
• High 7.6
  CVE-2026-85197

  Libsoup: libsoup: heap use-after-free in libsoup http/2 client on_data_read() via goaway during body upload

  A flaw was found in libsoup. A malicious HTTP/2 server or a Man-in-the-Middle (MITM) attacker can exploit a heap use-after-free vulnerability in the HTTP/2 client implementation. This occurs when a GNOME application uploads a file using HTTP/2, and the server…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 7 Linux Debian Ubuntu Azure Linux
  Sep 4, 2026
• High 7.5
  CVE-2026-15709

  Soupwebsocketextensiondeflate: libsoup: libsoup: websocket permessage-deflate unbounded decompression remote denial of service

  A flaw was found in libsoup's WebSocket implementation when using the permessage-deflate extension. The extension's decompression loop (inflate()) processes data in chunks without enforcing an upper boundary limit on the output buffer size. While libsoup limi…

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 7 Linux Debian Ubuntu Azure Linux
  Jul 14, 2026
• High 7.5
  CVE-2026-15711

  Libsoup: soupwebsocketconnection: libsoup: websocket remote denial of service via oversized control frame protocol violation

  A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 §5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or …

  Red Hat Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 7 Linux Debian Ubuntu Azure Linux
  Jul 14, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#important
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2499922
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2499924
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2528425
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543224
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543229
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543231
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543274
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543285
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2543296
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_98560.json
• report
  https://access.redhat.com/security/cve/CVE-2026-15709
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-15709
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-15709
• article
  https://gitlab.gnome.org/GNOME/libsoup/-/issues/511
• report
  https://access.redhat.com/security/cve/CVE-2026-15711
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-15711
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-15711
• article
  https://gitlab.gnome.org/GNOME/libsoup/-/issues/515
• report
  https://access.redhat.com/security/cve/CVE-2026-85197
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-85197
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-85197
• article
  https://gitlab.gnome.org/GNOME/libsoup/-/work_items/552
• report
  https://access.redhat.com/security/cve/CVE-2026-102555
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-102555
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-102555
• report
  https://access.redhat.com/security/cve/CVE-2026-102556
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-102556
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-102556
• report
  https://access.redhat.com/security/cve/CVE-2026-102557
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-102557
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-102557
• report
  https://access.redhat.com/security/cve/CVE-2026-102558
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-102558
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-102558
• report
  https://access.redhat.com/security/cve/CVE-2026-102559
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-102559
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-102559
• report
  https://access.redhat.com/security/cve/CVE-2026-102560