{
  "cveId": "CVE-2026-66338",
  "url": "https://patchblox.com/security/cve/CVE-2026-66338",
  "summary": "CVE-2026-66338 is fixed in 10 products on 1 platform, first by ALAS2023-2026-3212, released November 7, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "libsoup: Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities:\nCVE-2026-66338:\n\tA flaw w...",
  "description": "Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities:\nCVE-2026-66338:\n\tA flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.\n\nCVE-2026-66337:\n\tA flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.\n\nCVE-2026-15714:\n\tAn out-of-bounds read vulnerability was found in libsoup\u0027s multipart processing subsystem. The flaw exists in the soup_multipart_input_stream_read_headers() function inside soup-multipart-input-stream.c, which does not adequately restrict or validate the size of incoming multipart boundary strings. When processing a crafted HTTP response containing a malformed or oversized boundary parameter, the internal stream reader reads past the allocated buffer bounds. A remote, unauthenticated attacker can exploit this behavior to cause a service denial (DoS) through application failure or potentially read fragments of unauthorized memory metadata.\n\nCVE-2026-103399:\n\tA flaw was found in SoupServer (libsoup). When an HTTP/1.x client sends a request with Expect: 100-continue and a request body, and SoupServer returns an early final (non-1xx) response before the body is read, the server neither drains the declared body bytes nor closes the connection. On a keep-alive connection, those leftover bytes are interpreted as a subsequent HTTP request. A remote, unauthenticated attacker can place a complete HTTP request in the body and cause SoupServer to process that smuggled request, leading to unintended request handling.\n\nCVE-2026-102560:\n\tA 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 buffer overflow.\n\nCVE-2026-102559:\n\tA 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 overflow.\n\nCVE-2026-102558:\n\tA 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 data.\n\nCVE-2026-102557:\n\tA 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 while the implementation still used the full length, leading to heap corruption or a crash.\n\nCVE-2026-102556:\n\tA 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 documented GBytes API can trigger heap corruption or a crash upon receiving a crafted Pong.",
  "published": "2026-10-12T09:00:00Z",
  "severity": "important",
  "epss": 0.00291,
  "epssPercentile": 0.2182,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libsoup",
      "release": "amzn 2023",
      "fixedVersion": "2.72.0-6.amzn2023.0.16",
      "fix": "ALAS2023-2026-3212",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3212",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "2.72.0-6.amzn2023.0.16",
      "fix": "ALAS2023-2026-3212",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3212",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "2.72.0-6.amzn2023.0.16",
      "fix": "ALAS2023-2026-3212",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3212",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup-devel",
      "release": "amzn 2023",
      "fixedVersion": "2.72.0-6.amzn2023.0.16",
      "fix": "ALAS2023-2026-3212",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3212",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup-doc",
      "release": "amzn 2023",
      "fixedVersion": "2.72.0-6.amzn2023.0.16",
      "fix": "ALAS2023-2026-3212",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3212",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup3",
      "release": "amzn 2023",
      "fixedVersion": "3.7.3-1.amzn2023",
      "fix": "ALAS2023-2026-3240",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3240",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup3-debuginfo",
      "release": "amzn 2023",
      "fixedVersion": "3.7.3-1.amzn2023",
      "fix": "ALAS2023-2026-3240",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3240",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup3-debugsource",
      "release": "amzn 2023",
      "fixedVersion": "3.7.3-1.amzn2023",
      "fix": "ALAS2023-2026-3240",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3240",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup3-devel",
      "release": "amzn 2023",
      "fixedVersion": "3.7.3-1.amzn2023",
      "fix": "ALAS2023-2026-3240",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3240",
      "released": "2026-11-07T01:06:07Z"
    },
    {
      "platform": "linux",
      "product": "libsoup3-doc",
      "release": "amzn 2023",
      "fixedVersion": "3.7.3-1.amzn2023",
      "fix": "ALAS2023-2026-3240",
      "url": "https://patchblox.com/security/fix/linux/alas2023-2026-3240",
      "released": "2026-11-07T01:06:07Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-10T13:56:55Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}