TI-2026-77265 Aliases CVE-2026-87864 GHSA-mxp6-wxxv-r9rj

Command injection in curl IMAP APPEND when CRLF conversion is enabled

HIGH 70CWE-130Published 2026-10-20 · Updated 2026-10-30

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: —
Confidentiality · integrity · availability: High · High · High
Fix status: Partial Red Hat: 1 fixed, 5 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

The curl command line tool and library, in the individually listed releases from 7.30.0 through 8.21.0, mishandles IMAP APPEND when CURLOPT_CRLF is enabled. The IMAP APPEND literal advertises the raw input byte count while line-ending expanded data is sent, a length parameter inconsistency (CWE-130). A remote attacker with no privileges and no user interaction can exploit this, with high complexity, to run the leftover bytes as pipelined IMAP commands within an authenticated session.

Written with Claude Haiku 5.5 from the sources below · 2026-11-07

Description from the CNA

Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the authenticated session.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00828 57th percentileScored 2026-11-07

Fix Partial Red Hat: 1 advisoryRed Hat: 1 fixed, 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
curl	curl	8.21.0 – 8.21.0; 8.20.0 – 8.20.0; 8.19.0 – 8.19.0; 8.18.0 – 8.18.0; 8.17.0 – 8.17.0; 8.16.0 – 8.16.0; 8.15.0 – 8.15.0; 8.14.1 – 8.14.1; 8.14.0 – 8.14.0; 8.13.0 – 8.13.0; 8.12.1 – 8.12.1; 8.12.0 – 8.12.0; 8.11.1 – 8.11.1; 8.11.0 – 8.11.0; 8.10.1 – 8.10.1; 8.10.0 – 8.10.0; 8.9.1 – 8.9.1; 8.9.0 – 8.9.0; 8.8.0 – 8.8.0; 8.7.1 – 8.7.1; 8.7.0 – 8.7.0; 8.6.0 – 8.6.0; 8.5.0 – 8.5.0; 8.4.0 – 8.4.0; 8.3.0 – 8.3.0; 8.2.1 – 8.2.1; 8.2.0 – 8.2.0; 8.1.2 – 8.1.2; 8.1.1 – 8.1.1; 8.1.0 – 8.1.0; 8.0.1 – 8.0.1; 8.0.0 – 8.0.0; 7.88.1 – 7.88.1; 7.88.0 – 7.88.0; 7.87.0 – 7.87.0; 7.86.0 – 7.86.0; 7.85.0 – 7.85.0; 7.84.0 – 7.84.0; 7.83.1 – 7.83.1; 7.83.0 – 7.83.0; 7.82.0 – 7.82.0; 7.81.0 – 7.81.0; 7.80.0 – 7.80.0; 7.79.1 – 7.79.1; 7.79.0 – 7.79.0; 7.78.0 – 7.78.0; 7.77.0 – 7.77.0; 7.76.1 – 7.76.1; 7.76.0 – 7.76.0; 7.75.0 – 7.75.0; 7.74.0 – 7.74.0; 7.73.0 – 7.73.0; 7.72.0 – 7.72.0; 7.71.1 – 7.71.1; 7.71.0 – 7.71.0; 7.70.0 – 7.70.0; 7.69.1 – 7.69.1; 7.69.0 – 7.69.0; 7.68.0 – 7.68.0; 7.67.0 – 7.67.0; 7.66.0 – 7.66.0; 7.65.3 – 7.65.3; 7.65.2 – 7.65.2; 7.65.1 – 7.65.1; 7.65.0 – 7.65.0; 7.64.1 – 7.64.1; 7.64.0 – 7.64.0; 7.63.0 – 7.63.0; 7.62.0 – 7.62.0; 7.61.1 – 7.61.1; 7.61.0 – 7.61.0; 7.60.0 – 7.60.0; 7.59.0 – 7.59.0; 7.58.0 – 7.58.0; 7.57.0 – 7.57.0; 7.56.1 – 7.56.1; 7.56.0 – 7.56.0; 7.55.1 – 7.55.1; 7.55.0 – 7.55.0; 7.54.1 – 7.54.1; 7.54.0 – 7.54.0; 7.53.1 – 7.53.1; 7.53.0 – 7.53.0; 7.52.1 – 7.52.1; 7.52.0 – 7.52.0; 7.51.0 – 7.51.0; 7.50.3 – 7.50.3; 7.50.2 – 7.50.2; 7.50.1 – 7.50.1; 7.50.0 – 7.50.0; 7.49.1 – 7.49.1; 7.49.0 – 7.49.0; 7.48.0 – 7.48.0; 7.47.1 – 7.47.1; 7.47.0 – 7.47.0; 7.46.0 – 7.46.0; 7.45.0 – 7.45.0; 7.44.0 – 7.44.0; 7.43.0 – 7.43.0; 7.42.1 – 7.42.1; 7.42.0 – 7.42.0; 7.41.0 – 7.41.0; 7.40.0 – 7.40.0; 7.39.0 – 7.39.0; 7.38.0 – 7.38.0; 7.37.1 – 7.37.1; 7.37.0 – 7.37.0; 7.36.0 – 7.36.0; 7.35.0 – 7.35.0; 7.34.0 – 7.34.0; 7.33.0 – 7.33.0; 7.32.0 – 7.32.0; 7.31.0 – 7.31.0; 7.30.0 – 7.30.0	—	No fix listed	CNA

curl Vendorcurl Affected 8.21.0 – 8.21.0; 8.20.0 – 8.20.0; 8.19.0 – 8.19.0; 8.18.0 – 8.18.0; 8.17.0 – 8.17.0; 8.16.0 – 8.16.0; 8.15.0 – 8.15.0; 8.14.1 – 8.14.1; 8.14.0 – 8.14.0; 8.13.0 – 8.13.0; 8.12.1 – 8.12.1; 8.12.0 – 8.12.0; 8.11.1 – 8.11.1; 8.11.0 – 8.11.0; 8.10.1 – 8.10.1; 8.10.0 – 8.10.0; 8.9.1 – 8.9.1; 8.9.0 – 8.9.0; 8.8.0 – 8.8.0; 8.7.1 – 8.7.1; 8.7.0 – 8.7.0; 8.6.0 – 8.6.0; 8.5.0 – 8.5.0; 8.4.0 – 8.4.0; 8.3.0 – 8.3.0; 8.2.1 – 8.2.1; 8.2.0 – 8.2.0; 8.1.2 – 8.1.2; 8.1.1 – 8.1.1; 8.1.0 – 8.1.0; 8.0.1 – 8.0.1; 8.0.0 – 8.0.0; 7.88.1 – 7.88.1; 7.88.0 – 7.88.0; 7.87.0 – 7.87.0; 7.86.0 – 7.86.0; 7.85.0 – 7.85.0; 7.84.0 – 7.84.0; 7.83.1 – 7.83.1; 7.83.0 – 7.83.0; 7.82.0 – 7.82.0; 7.81.0 – 7.81.0; 7.80.0 – 7.80.0; 7.79.1 – 7.79.1; 7.79.0 – 7.79.0; 7.78.0 – 7.78.0; 7.77.0 – 7.77.0; 7.76.1 – 7.76.1; 7.76.0 – 7.76.0; 7.75.0 – 7.75.0; 7.74.0 – 7.74.0; 7.73.0 – 7.73.0; 7.72.0 – 7.72.0; 7.71.1 – 7.71.1; 7.71.0 – 7.71.0; 7.70.0 – 7.70.0; 7.69.1 – 7.69.1; 7.69.0 – 7.69.0; 7.68.0 – 7.68.0; 7.67.0 – 7.67.0; 7.66.0 – 7.66.0; 7.65.3 – 7.65.3; 7.65.2 – 7.65.2; 7.65.1 – 7.65.1; 7.65.0 – 7.65.0; 7.64.1 – 7.64.1; 7.64.0 – 7.64.0; 7.63.0 – 7.63.0; 7.62.0 – 7.62.0; 7.61.1 – 7.61.1; 7.61.0 – 7.61.0; 7.60.0 – 7.60.0; 7.59.0 – 7.59.0; 7.58.0 – 7.58.0; 7.57.0 – 7.57.0; 7.56.1 – 7.56.1; 7.56.0 – 7.56.0; 7.55.1 – 7.55.1; 7.55.0 – 7.55.0; 7.54.1 – 7.54.1; 7.54.0 – 7.54.0; 7.53.1 – 7.53.1; 7.53.0 – 7.53.0; 7.52.1 – 7.52.1; 7.52.0 – 7.52.0; 7.51.0 – 7.51.0; 7.50.3 – 7.50.3; 7.50.2 – 7.50.2; 7.50.1 – 7.50.1; 7.50.0 – 7.50.0; 7.49.1 – 7.49.1; 7.49.0 – 7.49.0; 7.48.0 – 7.48.0; 7.47.1 – 7.47.1; 7.47.0 – 7.47.0; 7.46.0 – 7.46.0; 7.45.0 – 7.45.0; 7.44.0 – 7.44.0; 7.43.0 – 7.43.0; 7.42.1 – 7.42.1; 7.42.0 – 7.42.0; 7.41.0 – 7.41.0; 7.40.0 – 7.40.0; 7.39.0 – 7.39.0; 7.38.0 – 7.38.0; 7.37.1 – 7.37.1; 7.37.0 – 7.37.0; 7.36.0 – 7.36.0; 7.35.0 – 7.35.0; 7.34.0 – 7.34.0; 7.33.0 – 7.33.0; 7.32.0 – 7.32.0; 7.31.0 – 7.31.0; 7.30.0 – 7.30.0 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:haxx:curl::::::::	—	—	Haxx

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* Versions — — ·Haxx

Remediation

The sources list no fixed version for curl. Red Hat fixes Red Hat Hardened Images in RHSA-2026:82895, released 2026-10-14. Red Hat lists no available plan for Red Hat Enterprise Linux 8, 9 and 10 or Red Hat Satellite 6, and gives no plan for Red Hat OpenShift AI (RHOAI).

Written with Claude Haiku 5.5 from the sources below · 2026-11-07

Red Hat 1 advisory

RHSA-2026:82895 Released 2026-10-14 · Red Hat rating Important
Red Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images curl-8.23.0-0.1.hum1@aarch64, curl-8.23.0-0.1.hum1@s390x, curl-8.23.0-0.1.hum1@src +10

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet
Red Hat OpenShift AI (RHOAI)	Affected	—
Red Hat Satellite 6	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Fixed	RHSA-2026:82895

Not affected: 8 products

Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 9
Red Hat Hardened Images
Red Hat JBoss Core Services
Red Hat OpenShift AI (RHOAI)
Red Hat Satellite 6

Timeline

2026-10-21 Threatist record created from CVE-2026-87864
2026-10-21 Alias added: GHSA-mxp6-wxxv-r9rj
2026-10-23 Affected versions changed · Red Hat
2026-10-30 CVSS score added · CISA ADP
2026-10-30 Weakness changed · CISA ADP
2026-10-30 CISA SSVC decision points changed
2026-10-30 Priority changed: LOW → HIGH
2026-10-31 EPSS moved to the 50th–90th percentile
2026-11-07 Affected versions changed · Red Hat

References

Other 3

TI-2023-19922 Out-of-bounds write in curl CVSS 3.1CRITICAL 9.8
TI-2026-16162 Negotiate ambient user conn reuse CVSS 3.1CRITICAL 9.8
TI-2026-10231 cross-origin Digest auth state leak CVSS 3.1CRITICAL 9.8
TI-2026-09063 HTTP/2 stream-dependency tree UAF CVSS 3.1CRITICAL 9.8
TI-2026-07976 stale proxy password leak CVSS 3.1CRITICAL 9.8
TI-2026-07845 SASL double-free CVSS 3.1CRITICAL 9.8

See all 103 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences