CVE Intelligence
Low Memory corruption

CVE-2018-1000030 — Use After Free in Canonical Ubuntu Linux

Python 2.7.14 is vulnerable to a Heap-Buffer-Overflow as well as a Heap-Use-After-Free. Python versions prior to 2.7.14 may also be vulnerable and it appears that Python 2.7.17 and prior may also be vulnerable however this has not been confirmed. The vulnerability lies when multiply threads are handling large amounts of data. In both cases there is essentially a race condition that occurs. For the Heap-Buffer-Overflow, Thread 2 is creating the size for a buffer, but Thread1 is already writing to the buffer without knowing how much to write. So when a large amount of data is being processed, it is very easy to cause memory corruption using a Heap-Buffer-Overflow. As for the Use-After-Free, Thread3->Malloc->Thread1->Free's->Thread2-Re-uses-Free'd Memory. The PSRT has stated that this is not a security vulnerability due to the fact that the attacker must be able to run code, however in some situations, such as function as a service, this vulnerability can potentially be used by an attacker to violate a trust boundary, as such the DWF feels this issue deserves a CVE.

Published Feb 8, 2018 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: mitre

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 1.2% (30-day exploitation probability)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
1.19%
ahead of 67% of scored CVEs · Oct 14, 2026
Affects
Canonical
Ubuntu Linux and 1 more
CVSS base
3.6
Low · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — bugs.python.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Canonical Ubuntu Linux, Python Python).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Canonical Ubuntu Linux version 12.04version 14.04version 16.04version 18.04 Vulnerable NIST National Vulnerability Database
Python Python ≤ 2.7.14 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
3.6 CVSS 3.1 Low 1.0 2.5 nvd@nist.gov via NIST National Vulnerability Database
3.6 CVSS 3.0 Low 1.0 2.5 cve@mitre.org via NIST National Vulnerability Database
3.6 CVSS 3.0 Low — — mitre via CVE Program (cve.org) e CISA ADP
3.3 CVSS 2.0 Low 3.4 4.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:L (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-416 · Use After Free

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 1.19%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 3.6
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2018
  • CVE published
    Feb 8, 2018 · mitre

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

7 on the record

Elsewhere on this site

Canonical
every CVE for this vendor
Memory corruption
same class
CWE-416
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-15308 Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations Jul 9, 2026
  • CVE-2026-4360 Tarfile.extract() doesn't fully respect filter parameter Jun 30, 2026
  • CVE-2026-0864 Configuration Injection via Carriage Return (\r) in write() method Jun 23, 2026
  • CVE-2026-47334 Deadlock or kernel panic in Ubuntu Linux AppArmor notification handling May 28, 2026
  • CVE-2026-47333 Out-of-bounds read in Ubuntu Linux AppArmor notification handling May 28, 2026
  • CVE-2026-47337 NULL pointer dereference in Ubuntu Linux AppArmor IPv4/IPv6 socket mediation May 28, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2018-1000030 is "Use After Free in Canonical Ubuntu Linux", rated Low. It affects Ubuntu Linux (Canonical); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.6 describes technical severity. EPSS 1.19% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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