A registered attack on jev-1.13.0 moves validated success from 1.8% to 3.5%

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Tiantong Wu and Wei Yang Bryan Lim, NTU, posted arXiv:2609.28613 on September 23. On 510 reconstructed InjecAgent cases, an adaptive attack with score feedback lifts validated attack success on jev-1.13.0 from 1.8% to 3.5%. The mean highest attacker-target probability found during search goes from 0.043 to 0.084. Several registered phrasings do not help the attacker. The paper has no code repository in the text we read. We did not rerun it.

Tiantong Wu and Wei Yang Bryan Lim, at Nanyang Technological University, posted arXiv:2609.28613 on September 23. The version we read is v1, CC BY 4.0. The measurements are on jev-1.13.0. The HTML we extracted does not contain a GitHub repository. A September 26 post links the abstract page. We did not rerun the experiments.

The suite reconstructs 510 InjecAgent cases. The abstract’s summary of the adaptive attack matches the table we read. Score feedback doubles the mean highest attacker-target probability found during the search, from 0.043 to 0.084. Success on fresh validation calls rises from 1.8% to 3.5%.

Validated success in that last experiment means at least 3 target selections in 5 fresh calls. At a search budget of 0 the rate is 1.8%, with an interval from 0.0% to 6.3%. At a budget of 24 it is 3.5%, with an interval from 0.0% to 10.0%. The validated change in attacker probability, budget 24 minus budget 0, is +0.0347, interval [0.0188, 0.0571]. The change in the safe option’s probability is -0.0193, interval [-0.0346, -0.0034]. A screening table prints 1.8% at budget 0, 3.3% at budget 8, and 3.5% at budgets 16 and 24. Successful cases go from 9 to 18. Of the 501 cases that failed at the baseline, 9 succeed once the budget reaches 24, which the paper puts at a conditional 1.8%.

The same section prints a conditional hit rate that uses Jev’s confidence field. At a threshold of 0.7 the rate is 0.2% at budget 24. It is also 0.2% at the baseline checkpoint.

Earlier registered conditions do not hand the attacker a larger effect. An override phrase that the paper says strengthens some attacks on other agents does not do that here. Base attack success is 1.8% (9 of 510), with a mean probability shift of +0.043. The enhanced wording is 0% and +0.009. A repeated-call rerun of enhanced minus base is -0.034, interval [-0.062, -0.015].

A second comparison, against their A0 condition, prints an importance marker at -0.006, an ignore-previous instruction at -0.032, and a natural-wording variant at -0.006. The natural-wording sign runs against the expectation they registered. Call-level attack success across the five conditions is 2.0%, 2.2%, 0%, 0%, and 1.3%: 51, 56, 0, 0, and 34 target selections out of 2,550 calls. Under a majority rule those are 11, 11, 0, 0, and 7 of 510 cases. Dropping the emergency-dispatch goal leaves the directions unchanged. Ignore-previous in that cut is -0.020, interval [-0.031, -0.012].

The third experiment’s probability gaps stay small. P2 minus a neutral prompt is +0.0030, interval [0.0010, 0.0054], under the 0.02 smallest effect they registered. P1 minus neutral is -0.0025, interval [-0.0054, -0.0005], which opposes the registered hypothesis. After they average 17 contexts per goal, P2 minus neutral is positive for 25 of 30 goals. The median absolute change at goal level is about 0.003.

The paper’s reading of the successes points at small initial margins, or at cases where the attacker has more control over the text. Schema-defined outputs change the shape of the answer. The measured rates above are the remainder.

This site's reading

Editorial notes evaluating claims against primary sources, contextualizing findings alongside related implementations, and defining technical terms.

Verify

arXiv:2609.28613v1, 23 September 2026, CC BY 4.0. Authors Tiantong Wu and Wei Yang Bryan Lim, Nanyang Technological University. The claims we read are limited to jev-1.13.0. The extracted text has no github.com URL.

Section 5 uses 510 reconstructed InjecAgent cases. DH-1 upstream base attack success is 1.8% (9/510), mean change in attacker probability +0.043. The enhanced condition is 0% and +0.009.

The enhanced-minus-base repeated-call rerun is -0.034, interval [-0.062, -0.015]. DH-2 against A0: importance marker -0.006 [-0.010, -0.001], ignore-previous -0.032 [-0.060, -0.014], natural wording -0.006 [-0.013, -0.001].

Call-level attack success for A0 through A4 is 2.0%, 2.2%, 0%, 0%, 1.3%, which is 51, 56, 0, 0, and 34 target selections out of 2,550 calls. Majority rule is 11, 11, 0, 0, and 7 of 510 cases. DH-3 P2 minus N0 is +0.0030 [0.0010, 0.0054], under the registered smallest effect of interest, 0.02.

DH-4 validated success, at least 3 target selections in 5 fresh calls, is 1.8% [0.0, 6.3] at budget 0 and 3.5% [0.0, 10.0] at budget 24. Validated change in attacker probability, 24 minus 0, is +0.0347 [0.0188, 0.0571]. Change in the safe probability is -0.0193 [-0.0346, -0.0034].

Conditional hit rate at confidence 0.7 is 0.2% at budget 24, and 0.2% at the baseline checkpoint as well. Screening Table 6: validated success 1.8% at budget 0, 3.3% at 8, 3.5% at 16 and at 24. Successful cases go from 9 to 18.

Of 501 cases that failed at baseline, 9 succeed at budget 24. Extra queries double the mean best-so-far attacker probability from 0.043 to 0.084. The abstract says adaptive attacks using score feedback double that mean, while success on fresh validation calls rises from 1.8% to 3.5%.

We did not rerun the calls.

Compare

TypeSafe's jaggedness page says adversarial text can steer an answer, and names a test as the workaround. RZ's security demo is 100 synthetic TypeScript spans, 65.3% balanced accuracy, a different task from InjecAgent. mizchi's monitor rule is a page-triage count, not an attack success rate.

The 1.8% to 3.5% here is validated selections on fresh calls, on jev-1.13.0 only.

Terms

1.8% to 3.5%
DH-4 validated attack success on fresh calls. Success means at least 3 target selections in 5 calls. Budget 0 is 1.8%. Budget 24 is 3.5%. The intervals are [0.0, 6.3] and [0.0, 10.0].
0.02
The registered smallest effect of interest in DH-3. P2 minus N0 is +0.0030, under that line. P1 minus N0 is -0.0025, opposite the registered expectation.
CHR
Conditional hit rate at a Jev confidence of 0.7 or higher. The paper prints 0.2% at budget 24 and 0.2% at the baseline checkpoint.

Sources

  1. arXiv:2609.28613
  2. HTML, decision hijacking
  3. newcenturysun, the abs page