TI-2021-20962 Aliases CVE-2021-45960 GHSA-pfmv-2r4f-j9mj

In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the…

HIGH 73CWE-682Published 2022-01-01 · Updated 2026-10-14

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: High · High · High
Fix status: Partial Red Hat: 12 fixed, 4 without a fix

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

Summary

In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory).

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.04672 91st percentileScored 2026-11-07

Public exploit Yes 2 exploit referencesTagged by NVD

Fix Partial Red Hat: 5 advisoriesRed Hat: 12 fixed, 4 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
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 11

CPE	Versions	Role	Vendor
cpe:2.3:a:libexpat_project:libexpat::::::::	before 2.4.3	Vulnerable	libexpat project
cpe:2.3:a:tenable:nessus::::::::	before 8.15.3; 10.0.0 to before 10.1.1	Vulnerable	Tenable
cpe:2.3:o:debian:debian_linux:10.0:::::::*	10.0	Vulnerable	Debian
cpe:2.3:o:debian:debian_linux:11.0:::::::*	11.0	Vulnerable	Debian
cpe:2.3:a:siemens:sinema_remote_connect_server::::::::	before 3.1	Vulnerable	Siemens
cpe:2.3:a:netapp:active_iq_unified_manager:-:::::vmware_vsphere::	not specified by NVD	Vulnerable	NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h610c:::::::*	h610c	Vulnerable	NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h610s:::::::*	h610s	Vulnerable	NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h615c:::::::*	h615c	Vulnerable	NetApp
cpe:2.3:a:netapp:oncommand_workflow_automation:-:::::::*	not specified by NVD	Vulnerable	NetApp

cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:* Versions before 2.4.3 Vulnerable ·libexpat project
cpe:2.3:a:tenable:nessus:*:*:*:*:*:*:*:* Versions before 8.15.3; 10.0.0 to before 10.1.1 Vulnerable ·Tenable
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian
cpe:2.3:a:siemens:sinema_remote_connect_server:*:*:*:*:*:*:*:* Versions before 3.1 Vulnerable ·Siemens
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* Versions not specified by NVD Vulnerable ·NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h610c:*:*:*:*:*:*:* Versions h610c Vulnerable ·NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h610s:*:*:*:*:*:*:* Versions h610s Vulnerable ·NetApp
cpe:2.3:a:netapp:hci_baseboard_management_controller:h615c:*:*:*:*:*:*:* Versions h615c Vulnerable ·NetApp
cpe:2.3:a:netapp:oncommand_workflow_automation:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp

Show 1 more CPE

CPE	Versions	Role	Vendor
cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:::::::*	not specified by NVD	Vulnerable	NetApp

cpe:2.3:a:netapp:solidfire_\&_hci_management_node:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp

Remediation

Red Hat 5 advisories

RHSA-2025:22871 Released 2025-12-09 · Red Hat rating Important
expat security update
- Red Hat Enterprise Linux BaseOS AUS (v. 8.2) expat-2.2.10-1.el8_2
RHSA-2025:22785 Released 2025-12-04 · Red Hat rating Important
expat security update
- Red Hat Enterprise Linux BaseOS AUS (v.8.4) expat-2.2.10-1.el8_4
- Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) expat-2.2.10-1.el8_4
RHSA-2022:7144 Released 2022-10-26 · Red Hat rating Important
Red Hat JBoss Core Services Apache HTTP Server 2.4.51 security update
- Red Hat JBoss Core Services

Show 2 more Red Hat advisories

RHSA-2022:1069 Released 2022-03-28 · Red Hat rating Important
expat security update
- Red Hat Enterprise Linux Client (v. 7) expat-2.1.0-14.el7_9
- Red Hat Enterprise Linux Client Optional (v. 7) expat-devel-2.1.0-14.el7_9, expat-static-2.1.0-14.el7_9
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) expat-devel-2.1.0-14.el7_9, expat-static-2.1.0-14.el7_9
- Red Hat Enterprise Linux Server (v. 7) expat-2.1.0-14.el7_9, expat-2.1.0-14.el7_9.ppc, expat-devel-2.1.0-14.el7_9 +1
- Red Hat Enterprise Linux Server Optional (v. 7) expat-static-2.1.0-14.el7_9, expat-static-2.1.0-14.el7_9.ppc
- Red Hat Enterprise Linux Workstation (v. 7) expat-2.1.0-14.el7_9, expat-devel-2.1.0-14.el7_9
- Red Hat Enterprise Linux Workstation Optional (v. 7) expat-static-2.1.0-14.el7_9
RHSA-2022:0951 Released 2022-03-16 · Red Hat rating Important
expat security update
- Red Hat Enterprise Linux BaseOS (v. 8) expat-2.2.5-4.el8_5.3, expat-devel-2.2.5-4.el8_5.3

Vendor assessments

Red Hat

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

Product	Status	Plan or fix
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix yet
Red Hat Enterprise Linux 8	Affected	No fix yet
Red Hat Enterprise Linux 9	Affected	No fix yet
Red Hat Enterprise Linux BaseOS (v. 8)	Fixed	RHSA-2022:0951
Red Hat Enterprise Linux BaseOS AUS (v. 8.2)	Fixed	RHSA-2025:22871
Red Hat Enterprise Linux BaseOS AUS (v.8.4)	Fixed	RHSA-2025:22785
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)	Fixed	RHSA-2025:22785
Red Hat Enterprise Linux Client (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux Client Optional (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux ComputeNode Optional (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux Server (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux Server Optional (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux Workstation (v. 7)	Fixed	RHSA-2022:1069
Red Hat Enterprise Linux Workstation Optional (v. 7)	Fixed	RHSA-2022:1069
Red Hat JBoss Core Services	Fixed	RHSA-2022:7144

Not affected: 4 products

Red Hat Enterprise Linux 9
Red Hat Enterprise Linux BaseOS AUS (v. 8.2)
Red Hat Enterprise Linux BaseOS AUS (v.8.4)
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)

Timeline

2026-10-02 Threatist record created from CVE-2021-45960
2026-10-03 Alias added: GHSA-pfmv-2r4f-j9mj
2026-10-09 Fix available: RHSA-2022:7144 · Red Hat
2026-10-16 Fix available: Red Hat JBoss Core Services · Red Hat

References

Exploit 2

Patch 2

Advisory 5

Sources

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