CVE-2026-9669 | bz2.BZ2Decompressor reuse after error can cause a stack buffer overflow

bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught the resulting OSError and retried with the same decompressor, crafted input could cause the decompressor to resume from an invalid internal state and perform out-of-bounds writes to a stack buffer. This could crash the process when processing untrusted data.

Published: 2026-06-08 Last update: 2026-06-23 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-9669 is rated Moderate Risk (43.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.38%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-9669

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.07% 0.38% +0.31%
2 2026-06-14 0.04% 0.07% +0.02%
3 2026-06-09 — 0.04% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-9669

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 4.0 HIGH
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:H)
Exploitation depends on constrained or hard-to-reproduce conditions.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]

Weakness enumeration for CVE-2026-9669

GitHub Security Advisory for CVE-2026-9669

GHSA-8jvr-397x-xqh9 · Severity: high — bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught...

OS Trackers for CVE-2026-9669

vendor priority summary link
debian not yet assigned CVE-2026-9669 not yet assigned priority: Debian including 4 source packages (python3.11, python3.13, python3.14, python3.9), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 3. https://security-tracker.debian.org/tracker/CVE-2026-9669
suse medium CVE-2026-9669 severity moderate: SUSE including 18 source package names (python, python-32bit, …), 115 product×package rows across 22 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, … (22 product lines)): Known Not Affected 115. https://www.suse.com/security/cve/CVE-2026-9669/
ubuntu medium CVE-2026-9669 medium priority: Ubuntu including 12 source packages (python2.7, python3.10, …), 72 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 41, needs-triage 31. https://ubuntu.com/security/CVE-2026-9669

Affected software / configurations for CVE-2026-9669

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-9669

cvelogic Threat Intelligence