Fix CWE-93 newline injection in DOTENV DataSet writer - #626
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sfc-gh-ikryvanos wants to merge 1 commit into
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Fix CWE-93 newline injection in DOTENV DataSet writer#626sfc-gh-ikryvanos wants to merge 1 commit into
sfc-gh-ikryvanos wants to merge 1 commit into
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The dotenv SetDataByKey path wrote key=value unquoted and only prefixed a backslash before raw \n / \r bytes, so a caller authorized for a single data_key could embed a newline in the value and inject arbitrary extra environment variables (e.g. LD_PRELOAD) into the .env file, escalating a constrained single-key write into arbitrary env-var injection on the host at the next service start. Reject rather than escape: validate the key against a strict POSIX env-var charset ([A-Za-z_][A-Za-z0-9_]*) and reject any value containing a newline or other control character, failing closed before the file is opened so a rejected write changes nothing. A .env value cannot safely span physical lines in the unquoted single-line format the writer emits. Add TestIntegration regression coverage: the LD_PRELOAD PoC, CR and CRLF variants, a control-char value, malicious keys, the two-call rewrite sequence, and happy-path overwrite/append. Co-authored-by: Cursor <cursoragent@cursor.com>
sfc-gh-mjankowski
approved these changes
Aug 10, 2026
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The dotenv SetDataByKey path wrote key=value unquoted and only prefixed a backslash before raw \n / \r bytes, so a caller authorized for a single data_key could embed a newline in the value and inject arbitrary extra environment variables (e.g. LD_PRELOAD) into the .env file, escalating a constrained single-key write into arbitrary env-var injection on the host at the next service start.
Reject rather than escape: validate the key against a strict POSIX env-var charset ([A-Za-z_][A-Za-z0-9_]*) and reject any value containing a newline or other control character, failing closed before the file is opened so a rejected write changes nothing. A .env value cannot safely span physical lines in the unquoted single-line format the writer emits.
Add TestIntegration regression coverage: the LD_PRELOAD PoC, CR and CRLF variants, a control-char value, malicious keys, the two-call rewrite sequence, and happy-path overwrite/append.