CVE-2021-33456
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in...
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
CVE-2021-33456- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
CVE List No score
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
CVE-2021-33456- Updated
- 2026-11-02
EUVDEUVD-2021-20160 No score
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
EUVD-2021-20160- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-jm6f-2xgv-f2ch
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in...
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
GHSA-jm6f-2xgv-f2ch- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
OSVAZL-10326
CVE-2021-33456 affecting package yasm 1.3.0-17
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
AZL-10326- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVAZL-35366
CVE-2021-33456 affecting package yasm 1.3.0-17
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
AZL-35366- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-05
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OSV
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
CVE-2021-33456- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-33456
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
DEBIAN-CVE-2021-33456- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVJLSEC-2026-586
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
JLSEC-2026-586- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-33456
An issue was discovered in yasm version 1.3.0. There is a NULL pointer dereference in hash() in modules/preprocs/nasm/nasm-pp.c.
- Record
UBUNTU-CVE-2021-33456- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
yasmAzure Linux:2 |
through 1.3.0-17 | None known |
yasmAzure Linux:3 |
through 1.3.0-17 | None known |
yasmDebian:12 |
All versions, plus listed versions 1.3.0-41.3.0-51.3.0-61.3.0-71.3.0-8 |
None known |
yasmDebian:13 |
All versions, plus listed versions 1.3.0-71.3.0-8 |
None known |
yasmDebian:14 |
before 1.3.0-8, plus listed versions 1.3.0-7 |
1.3.0-8 |
YASM_jllJulia |
All versions | None known |
yasmUbuntu:16.04:LTS |
All versions, plus listed versions 1.3.0-2 |
None known |
yasmUbuntu:18.04:LTS |
All versions, plus listed versions 1.3.0-21.3.0-2build1 |
None known |
yasmUbuntu:20.04:LTS |
All versions, plus listed versions 1.3.0-2build11.3.0-2ubuntu1 |
None known |
yasmUbuntu:22.04:LTS |
All versions, plus listed versions 1.3.0-2.1 |
None known |
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| Package | Affected | Fixed |
|---|---|---|
yasmUbuntu:24.04:LTS |
All versions, plus listed versions 1.3.0-4 |
None known |
yasmUbuntu:25.10 |
All versions, plus listed versions 1.3.0-51.3.0-7 |
None known |
yasmUbuntu:26.10 |
All versions, plus listed versions 1.3.0-8 |
None known |
yasmUbuntu:26.04:LTS |
All versions, plus listed versions 1.3.0-71.3.0-8 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-33456 is a medium vulnerability (CVSS 5.5) in Tortall Yasm, published July 26, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 25th percentile. Fixed in yasm 1.3.0-8.