Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
A vulnerability exists in the csv.Sniffer.sniff() function of Python 3.10 used in Red Hat Hardened Images. The flaw causes super-linear regular expression processing when parsing specially crafted CSV input, leading to excessive CPU consumption and potential denial of service. Most applications are unaffected as they do not use this sniffing function on untrusted input. Red Hat has released an update for the affected RPM packages to address this issue.
AI Analysis
Technical Summary
CVE-2026-18503 is a denial of service vulnerability in Python's csv.Sniffer.sniff() function due to inefficient regular expression complexity (CWE-1333). When processing specially crafted CSV samples, the function can trigger super-linear CPU usage caused by excessive backtracking in regex matching. This can cause significant CPU resource consumption, potentially leading to denial of service in applications that invoke this function on untrusted or unbounded input. Red Hat Hardened Images shipping Python 3.10 RPMs are affected and have been updated to version 3.10.21-1.hum1 to fix this issue. The vulnerability is rated as low severity by Red Hat, as most applications do not use the sniff() function on untrusted data.
Potential Impact
The vulnerability can cause denial of service through excessive CPU consumption when the csv.Sniffer.sniff() function processes crafted CSV input. There is no impact on confidentiality or integrity. The impact is availability degradation limited to applications that use this function on untrusted or large CSV samples.
Mitigation Recommendations
Red Hat has released updated RPM packages for Python 3.10 that fix this issue. Users should apply these updates to mitigate the vulnerability. Additionally, avoid passing untrusted or unbounded CSV input to csv.Sniffer.sniff(). If dialect detection is required, limit the sample size passed to sniff() or use a known dialect directly with csv.reader().
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Description
A vulnerability exists in the csv.Sniffer.sniff() function of Python 3.10 used in Red Hat Hardened Images. The flaw causes super-linear regular expression processing when parsing specially crafted CSV input, leading to excessive CPU consumption and potential denial of service. Most applications are unaffected as they do not use this sniffing function on untrusted input. Red Hat has released an update for the affected RPM packages to address this issue.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-18503 is a denial of service vulnerability in Python's csv.Sniffer.sniff() function due to inefficient regular expression complexity (CWE-1333). When processing specially crafted CSV samples, the function can trigger super-linear CPU usage caused by excessive backtracking in regex matching. This can cause significant CPU resource consumption, potentially leading to denial of service in applications that invoke this function on untrusted or unbounded input. Red Hat Hardened Images shipping Python 3.10 RPMs are affected and have been updated to version 3.10.21-1.hum1 to fix this issue. The vulnerability is rated as low severity by Red Hat, as most applications do not use the sniff() function on untrusted data.
Potential Impact
The vulnerability can cause denial of service through excessive CPU consumption when the csv.Sniffer.sniff() function processes crafted CSV input. There is no impact on confidentiality or integrity. The impact is availability degradation limited to applications that use this function on untrusted or large CSV samples.
Mitigation Recommendations
Red Hat has released updated RPM packages for Python 3.10 that fix this issue. Users should apply these updates to mitigate the vulnerability. Additionally, avoid passing untrusted or unbounded CSV input to csv.Sniffer.sniff(). If dialect detection is required, limit the sample size passed to sniff() or use a known dialect directly with csv.reader().
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:57010
- Cve Count
- 1
- Additional Cves
- []
- Cvss Version
- null
Threat ID: 6a870a56acd9273b49b58636
Added to database: 08/20/2026, 14:08:22 UTC
Last enriched: 08/20/2026, 14:19:39 UTC
Last updated: 08/20/2026, 22:52:10 UTC
Views: 3
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