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amazonAmazonALAS2-2023-2307
HistoryOct 12, 2023 - 3:09 p.m.

Medium: libsepol

2023-10-1215:09:00
alas.aws.amazon.com
21
selinux
cil compiler
use-after-free
heap-based buffer over-read
amazon linux 2
update
libsepol

2.1 Low

CVSS2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:L/AC:L/Au:N/C:N/I:N/A:P

3.3 Low

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

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

7.1 High

AI Score

Confidence

Low

0.001 Low

EPSS

Percentile

40.7%

Issue Overview:

The CIL compiler in SELinux 3.2 has a use-after-free in __cil_verify_classperms (called from __cil_verify_classpermission and __cil_pre_verify_helper). (CVE-2021-36084)

The CIL compiler in SELinux 3.2 has a use-after-free in __cil_verify_classperms (called from __verify_map_perm_classperms and hashtab_map). (CVE-2021-36085)

The CIL compiler in SELinux 3.2 has a use-after-free in cil_reset_classpermission (called from cil_reset_classperms_set and cil_reset_classperms_list). (CVE-2021-36086)

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block. (CVE-2021-36087)

Affected Packages:

libsepol

Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.

Issue Correction:
Run yum update libsepol to update your system.

New Packages:

aarch64:  
    libsepol-2.5-10.amzn2.0.1.aarch64  
    libsepol-devel-2.5-10.amzn2.0.1.aarch64  
    libsepol-static-2.5-10.amzn2.0.1.aarch64  
    libsepol-debuginfo-2.5-10.amzn2.0.1.aarch64  
  
i686:  
    libsepol-2.5-10.amzn2.0.1.i686  
    libsepol-devel-2.5-10.amzn2.0.1.i686  
    libsepol-static-2.5-10.amzn2.0.1.i686  
    libsepol-debuginfo-2.5-10.amzn2.0.1.i686  
  
src:  
    libsepol-2.5-10.amzn2.0.1.src  
  
x86_64:  
    libsepol-2.5-10.amzn2.0.1.x86_64  
    libsepol-devel-2.5-10.amzn2.0.1.x86_64  
    libsepol-static-2.5-10.amzn2.0.1.x86_64  
    libsepol-debuginfo-2.5-10.amzn2.0.1.x86_64  

Additional References

Red Hat: CVE-2021-36084, CVE-2021-36085, CVE-2021-36086, CVE-2021-36087

Mitre: CVE-2021-36084, CVE-2021-36085, CVE-2021-36086, CVE-2021-36087

2.1 Low

CVSS2

Attack Vector

LOCAL

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:L/AC:L/Au:N/C:N/I:N/A:P

3.3 Low

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

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

7.1 High

AI Score

Confidence

Low

0.001 Low

EPSS

Percentile

40.7%