CVE-2023-27538 — An authentication bypass vulnerability exists in libcurl v8.0.0 where it reuses a previously...

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Broadcom Brocade Fabric Operating System Firmware, Debian Debian Linux, Fedoraproject Fedora…).
2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
3. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-287 · Improper Authentication

Other CVEs with this weakness →

EPSS over time FIRST

Oct 14, 2026 → Oct 15, 2026 · 2 reading(s) · max 1.45%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
• Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.

Timeline

What happened to this CVE, newest first.

• 2026
• SSVC assessment updated
  Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 14, 2026
• Affected products added · haxx/libcurl, fedoraproject/fedora, debian/debian linux, netapp/active iq unified manager, netapp/clustered data ontap,
  Oct 14, 2026 · NIST National Vulnerability Database
• CVSS changed · 5.5
  Oct 14, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 14, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 14, 2026 · Alertas do Telegram
• 2023
• CVE published
  Mar 30, 2023 · hackerone

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 14, 2026 – Oct 14, 2026
• 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

12 on the record

• nvd.nist.gov/vuln/detail/CVE-2023-27538
  GitHub Security Advisories
• security.netapp.com/advisory/ntap-20230420-0010/
  Third Party Advisory, NIST National Vulnerability Database
• cert-portal.siemens.com/productcert/html/ssa-398330.html
  NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/36NBD5
  GitHub Security Advisories
• hackerone.com/reports/1898475
  Exploit, Third Party Advisory, NIST National Vulnerability Database
• github.com/advisories/GHSA-cgj3-cvg6-pcvh
  GitHub Security Advisories
• cert-portal.siemens.com/productcert/html/ssa-943925.html
  NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20230420-0010
  GitHub Security Advisories
• lists.debian.org/debian-lts-announce/2023/04/msg00025.html
  Mailing List, mailing-list, NIST National Vulnerability Database
• security.gentoo.org/glsa/202310-12
  Third Party Advisory, vendor-advisory, NIST National Vulnerability Database
• cert-portal.siemens.com/productcert/html/ssa-077170.html
  NIST National Vulnerability Database
• curl.se/docs/CVE-2023-27538.html
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
• Medium CVE-2026-14355 ext/openssl: Memory corruption in openssl_encrypt with AES-WRAP-PAD Jul 3, 2026
• Medium CVE-2026-56968 Use of Uninitialized Resource in Gnu Sasl Jun 23, 2026
• Medium CVE-2026-54231 Abrt: unsanitized systemd journal content written to dump directory files enables content injection Jun 13, 2026
• High CVE-2026-54230 Abrt: event handler scripts follow symlinks when writing output files, allowing arbitrary file overwrites Jun 13, 2026
• High CVE-2026-49975 Apache HTTP Server: mod_http2 denial of service Jun 8, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No fixed version, patch or mitigation documented.
• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2023-27538 is "An authentication bypass vulnerability exists in libcurl v8.0.0 where it reuses a previously...", rated Medium. It affects Brocade Fabric Operating System Firmware (Broadcom); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 1.45% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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