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NVD / CVE Program· CNA mitre

CVE-2020-24978: In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c.

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.3% (FIRST EPSS); higher than 71.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: nasm (Debian:12) 2.15.04-1.

Low priority for now. Upgrade to nasm (Debian:12) 2.15.04-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In NASM 2.15.04rc3, there is a double-free vulnerability in pp_tokline asm/preproc.c. This is fixed in commit 8806c3ca007b84accac21dd88b900fb03614ceb7.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Sep 3, 2020
Updated
Jun 16, 2026
EPSS
1.3% · 71th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.3%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
nasmnetwide assembler

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • nasm netwide assembler2.15.04

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12nasmbefore 2.15.04-12.15.04-1

Same product

nasm: all records

Other highest-scoring records for the same primary product.

  • CVE-2004-1287Buffer overflow in the error function in preproc.c for NASM 0.98.38 1.2 allows attackers to execute arbitrary code via a crafted asm file, a
    45Plan
  • CVE-2026-6068NASM contains a heap use after free vulnerability in response file (-@) processing where a dangling pointer to freed memory is stored in the
    38Monitor
  • CVE-2008-7177Buffer overflow in the listing module in Netwide Assembler (NASM) before 2.03.01 has unknown impact and attack vectors, a different vulnerab
    38Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2020-24241Aug 25, 2020 · In Netwide Assembler (NASM) 2.15rc10, there is heap use-after-free in saa_wbytes in nasmlib/saa.c.
    22Monitor
  • ← EarlierCVE-2020-24242Aug 25, 2020 · In Netwide Assembler (NASM) 2.15rc10, SEGV can be triggered in tok_text in asm/preproc.c by accessing READ memory.
    22Monitor
  • Later →CVE-2020-18974Aug 25, 2021 · Buffer Overflow in Netwide Assembler (NASM) v2.15.xx allows attackers to cause a denial of service via 'crc64i' in the component 'nasmlib/cr
    13Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:nasm2.15.04-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-415 · Double Free

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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