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CVE-2026-121996— Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length

Quick assessment

Affected

Red Hat Red Hat Enterprise Linux 10

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

gdbserver 的代理表达式解析器中存在长度验证缺陷，使得未经身份验证的远程攻击者能够读取 gdbserver 进程中未初始化的堆内存，并导致拒绝服务（DoS）。泄露的堆内容包括可用于在后续利用中绕过地址空间布局随机化（ASLR）的地址信息。

CVSS 8.2 · High Updated Nov 06, 2026

Possible ATT&CK Techniques 3 AI

T1203 · Exploitation for Client Execution T1069 · Permission Groups Discovery T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length

Source: CVE Program / CVE List V5

Vulnerability Description

A length validation flaw in gdbserver's agent-expression parser allows an unauthenticated remote attacker to read uninitialized heap memory from the gdbserver process and cause a denial of service. Disclosed heap content includes addresses suitable for defeating ASLR in further exploitation.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

非可信指针解引用

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE
Red Hat	Red Hat Enterprise Linux 10	-	`cpe:/a:redhat:enterprise_linux:10`
Red Hat	Red Hat Enterprise Linux 10	-	`cpe:/a:redhat:enterprise_linux:10`
Red Hat	Red Hat Enterprise Linux 6	-	`cpe:/o:redhat:rhel_els:6`
Red Hat	Red Hat Enterprise Linux 7	-	`cpe:/o:redhat:rhel_els:7`
Red Hat	Red Hat Enterprise Linux 8	-	`cpe:/a:redhat:enterprise_linux:8`
Red Hat	Red Hat Enterprise Linux 8	-	`cpe:/a:redhat:enterprise_linux:8`
Red Hat	Red Hat Enterprise Linux 8	-	`cpe:/a:redhat:enterprise_linux:8`
Red Hat	Red Hat Enterprise Linux 8	-	`cpe:/a:redhat:enterprise_linux:8`
Red Hat	Red Hat Enterprise Linux 9	-	`cpe:/a:redhat:enterprise_linux:9`
Red Hat	Red Hat Enterprise Linux 9	-	`cpe:/a:redhat:enterprise_linux:9`
Red Hat	Red Hat Hardened Images	-	`cpe:/a:redhat:hummingbird:1`

II. Public POCs for CVE-2026-121996

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-121996

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Other References for CVE-2026-121996 (2)

https://access.redhat.com/security/cve/CVE-2026-121996 vdb-entry x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2565678 issue-tracking x_refsource_REDHAT

https://www.cve.org/CVERecord?id=CVE-2026-121996

Same Patch Batch · Red Hat · 2026-11-05 · 24 CVEs total

CVE-2026-117691	9.1 CRITICAL	Keycloak-services: keycloak-services: saml redirect binding signature bypass via percent-e
CVE-2026-97175	8.8 HIGH	Keycloak-services: keycloak-services: unverified idp email auto-linking enables account ta
CVE-2026-121994	8.8 HIGH	Gdb: gdb: stack buffer overflow in fetch_register_using_p via unchecked p-reply length
CVE-2026-92857	8.1 HIGH	Keycloak-services: keycloak-services: dcr protocol mapper config not validated, allowing i
CVE-2026-121997	8.1 HIGH	Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mis
CVE-2026-114232	8.1 HIGH	Keycloak-services: keycloak-services: uma protection api resourcetype field not validated
CVE-2026-112208	8.1 HIGH	Keycloak-services: keycloak-services: account takeover via stale sso_auth note in organiza
CVE-2026-96453	8.0 HIGH	Org.keycloak/keycloak-admin-cli: keycloak-admin-cli: kcadm custom truststore accepts arbit
CVE-2026-107912	7.7 HIGH	Io.quarkus/quarkus-vertx-http: quarkus-vertx-http: authorization bypass in management inte
CVE-2026-121995	7.5 HIGH	Gdb: gdb: stack buffer overflow in parse_tracepoint_definition via stale rs->buf tail
CVE-2026-107123	7.5 HIGH	Keycloak-services: keycloak-services: unauthenticated cpu denial of service via saml xml d
CVE-2026-103112	7.5 HIGH	Keycloak-services: keycloak-services: account takeover via authentication race using reset
CVE-2026-107602	7.5 HIGH	Keycloak-services: keycloak-services: unauthenticated cpu exhaustion via saml 1.1 keyinfo
CVE-2026-110931	7.5 HIGH	Keycloak-services: keycloak-services: unauthenticated jvm termination via saml 1.1 authori
CVE-2026-110932	7.5 HIGH	Keycloak-services: keycloak-services: unauthenticated persistent disk exhaustion via theme
CVE-2026-82965	7.5 HIGH	Keycloak-services: keycloak-services: unauthenticated denial of service via saml soap endp
CVE-2026-92855	7.4 HIGH	Keycloak-services: keycloak-services: saml broker accepts holder-of-key assertions without
CVE-2026-93998	7.4 HIGH	Keycloak-core: keycloak-core: saml adapter does not bind signed assertions to the configur
CVE-2026-97847	7.1 HIGH	Keycloak-services: keycloak-services: client manager can substitute sessionless token prin
CVE-2026-97174	6.8 MEDIUM	Keycloak-services: keycloak-services: ciba sub parameter injection causes attacker authent

Showing top 20 of 24 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Red Hat Enterprise Linux 10

Same vendor: Red Hat

Same weakness: CWE-822