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Vulnerabilities

Vulnerability · CVE-2026-18503

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.S

Published Aug 10, 2026 · catalog updated Oct 28, 2026 · Attacker-controlled CSV samples can

Last checked Oct 31, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-18503. EPSS is 0.12%. Act only if a listed version of Attacker-controlled CSV samples can is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Attacker-controlled CSV samples can).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.12%
Remediation
Advisory link
Affected products
Debian:12 pypy3 · Debian:12 python3.11 · Debian:13 pypy3 · Debian:13 python3.13 · Debian:14 pypy3 · Debian:14 python3.13

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 pypy37.3.11+dfsg-2, 7.3.11+dfsg-2+deb12u1, 7.3.11+dfsg-2+deb12u2
  • Debian:12 python3.110 → 3.11.2-6+deb12u9
  • Debian:13 pypy37.3.19+dfsg-2, 7.3.20+dfsg-1, 7.3.20+dfsg-2
  • Debian:13 python3.133.13.11-1, 3.13.12-1, 3.13.14-1
  • Debian:14 pypy30 → 8.0.1+dfsg-1
  • Debian:14 python3.130 → 3.13.15-1
  • Debian:14 python3.140 → 3.14.7-1
  • Debian:14 python3.150 → 3.15.0~rc1-1

How to fix CVE-2026-18503

  • Upgrade

    CVE-2026-18503 lists a fix boundary at 3.11.2-6+deb12u9. Compare the installed build with that boundary before you change production.

  • Version check

    Fixed in 3.11.2-6+deb12u9 · 11 other ranges on the advisory

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-18503. EPSS is 0.12%. Act only if a listed version of Attacker-controlled CSV samples can is installed.

Which versions are affected?

Compare what you have installed with 7.3.11+dfsg-2, 7.3.11+dfsg-2+deb12u1, 7.3.11+dfsg-2+deb12u2, 0 → 3.11.2-6+deb12u9, 7.3.19+dfsg-2, 7.3.20+dfsg-1, 7.3.20+dfsg-2, 3.13.11-1, 3.13.12-1, 3.13.14-1, 0 → 8.0.1+dfsg-1, 0 → 3.13.15-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.12%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 10, 2026 · Trivy Vulnerability DB

    Detected

    Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

  2. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    pypy3 fixed in 8.0.1+dfsg-1; python3.11 fixed in 3.11.2-6+deb12u9; python3.13 fixed in 3.13.15-1; python3.14 fixed in 3.14.7-1

  3. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    pypy3 fixed in 8.0.1+dfsg-1

  4. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    python3.11 fixed in 3.11.2-6+deb12u9

  5. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    python3.13 fixed in 3.13.15-1

  6. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    python3.14 fixed in 3.14.7-1

  7. Oct 28, 2026 · Trivy Vulnerability DB

    Fix available

    python3.15 fixed in 3.15.0~rc1-1

  8. Oct 28, 2026 · Trivy Vulnerability DB

    Updated

    Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

Sources

  • CVE.orgVulnerability recordCVE-2026-18503

    Official CVE identifier

    cve.org
  • Trivy Vulnerability DBPackage advisoryDEBIAN-CVE-2026-18503

    Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

    osv.dev

References

Freshness

Last verified in this catalog Oct 31, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 28, 2026
  • Trivy Vulnerability DBOct 28, 2026