Security Bulletin
Summary
Vulnerable version of libcurl in Informix
Vulnerability Details
CVEID: CVE-2026-13608
DESCRIPTION: A flaw in the libcurl SASL negotiation for LDAP authentication allows an
incomplete handshake sequence to be misinterpreted as a successful
cryptographic verification. An attacker executing a Man-in-the-Middle (MITM)
attack can inject a premature or shortcut response that bypasses complete peer
validation.
CWE: CWE-923: Improper Restriction of Communication Channel to Intended Endpoints
CVSS Source: CISA ADP
CVSS Base score: 7.4
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
CVEID: CVE-2026-18924
DESCRIPTION: A flaw in libcurl's handling of HTTP/2 Server Push streams, when the parent
handle is set to share connections with other handles, can lead to
use-after-free in the cleanup process.
CWE: CWE-416: Use After Free
CVSS Source: CISA ADP
CVSS Base score: 9.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H)
CVEID: CVE-2026-19931
DESCRIPTION: A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given
hostname using Negotiate authentication, when the initial request is done
using empty credentials. This can make user B's request get sent over user A's
previously authenticated connection.
CWE: CWE-488: Exposure of Data Element to Wrong Session
CVSS Source: CISA ADP
CVSS Base score: 9.8
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
CVEID: CVE-2026-80229
DESCRIPTION: When performing transfers via libcurl’s multi interface, pooled TLS
connections can outlive their originating easy handles. In OpenSSL 3 provider
configurations, libcurl attaches an allocated library context to the easy
handle's state and passes it to OpenSSL without acquiring an ownership
reference; destroying the easy handle prematurely frees this context while the
active connection retains a dangling pointer, leading to a heap-use-after-free
upon subsequent I/O or post-handshake operations.
CWE: CWE-416: Use After Free
CVSS Source: CISA ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2026-80230
DESCRIPTION: When `CURLOPT_PINNEDPUBLICKEY` is configured alongside options that disable
standard peer verification (`CURLOPT_SSL_VERIFYPEER = 0` and
`CURLOPT_SSL_VERIFYHOST = 0`), libcurl fails to enforce public key pinning on
connections established without a presented server certificate. Bypassing the
pinning check under these disabled-verification conditions allows
unauthenticated connections to succeed when they should be rejected.
CWE: CWE-295: Improper Certificate Validation
CVSS Source: CISA ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2026-80231
DESCRIPTION: A flaw in libcurl makes it wrongly reuse an existing HTTPS connection setup
for a given hostname even when using a different Native CA Store setting
(`CURLSSLOPT_NATIVE_CA`) than when the connection was created.
CWE: CWE-488: Exposure of Data Element to Wrong Session
CVSS Source: CISA ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2026-80255
DESCRIPTION: A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of
space (ascii code 32) immediately before the `Secure` attribute causes curl to
store the cookie without its Secure flag. The cookie might then wrongfully be
sent over plaintext HTTP on subsequent requests to the same host.
CWE: CWE-201: Insertion of Sensitive Information Into Sent Data
CVSS Source: CISA ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
CVEID: CVE-2026-82208
DESCRIPTION: With the wolfSSL backend, when CA caching is enabled and an
`CURLOPT_SSL_CTX_FUNCTION` callback replaces the trust store, libcurl can
silently reinstall the cached store after the callback returns. A certificate
trusted by the cached store but rejected by the callback-selected store is
then incorrectly accepted.
CWE: CWE-295: Improper Certificate Validation
CVSS Source: CISA ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
CVEID: CVE-2026-82209
DESCRIPTION: When libpsl support is enabled, libcurl fails to enforce the Public Suffix
List boundary check when processing a `Set-Cookie` header where the `Domain`
attribute explicitly matches an origin host that is itself a public suffix
(e.g., `Domain=co.uk` set by `co.uk`).
Instead of coercing it into a strict host-only cookie, libcurl saves the
cookie with wildcard domain scope (`.co.uk`). Consequently, the cookie is
inappropriately included in subsequent outbound requests or HTTP redirects to
arbitrary sibling subdomains under the same public suffix (e.g.,
`attacker.co.uk`).
CWE: CWE-201: Insertion of Sensitive Information Into Sent Data
CVSS Source: CISA ADP
CVSS Base score: 8.2
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM Informix Dynamic Server | 14.10 |
| IBM Informix Dynamic Server | 12.10 (out of support) |
| IBM Informix Dynamic Server | 15.0 |
Remediation/Fixes
Fix available in IDS-14.10.xC14W4, IDS-15.0.1.20 on Fix Central
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
12 Nov 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
12 November 2026
Initial Publish date:
12 November 2026
UID
ibm17296614